Editing Human nutrition

{{short description|Nutrients supporting human health}}
{{About||the journal|Human Nutrition (journal)|nutrition not specific to humans|Nutrition}}
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[[File:FoodSourcesOfMagnesium.jpg|thumb|Foods high in [[magnesium]] (an example of a [[nutrient]])]]
'''Human nutrition''' deals with the provision of [[essential nutrient]]s in food that are necessary to support human life and good health.<ref>{{cite web | title=human nutrition | url=https://www.britannica.com/science/human-nutrition | website=Encyclopedia Britannica | access-date=29 December 2020 | language=en | archive-date=11 July 2022 | archive-url=https://web.archive.org/web/20220711211342/https://www.britannica.com/science/human-nutrition | url-status=live}}</ref> Poor nutrition is a chronic problem often linked to [[poverty]], [[food security]], or a poor understanding of nutritional requirements.<ref name="Progress for Children">{{cite book | author=UNICEF | date=May 1, 2006 <!-- Date from press release at https://reliefweb.int/report/world/progress-children-report-card-nutrition --> | title=Progress for children: A report card on nutrition | volume=4 | publication-place=New York City | publisher=Author | isbn=978-92-806-3988-9 | oclc=68570771 | url=https://www.unicef.org/media/86536/file/Progress_for_Children_-_No._4.pdf <!-- https://data.unicef.org/wp-content/uploads/2015/12/Progress_for_Children_-_No._4_188.pdf https://www.unscn.org/web/archives_resources/files/Progress_for_Children_-_No._4.pdf https://reliefweb.int/attachments/10e88faa-fe88-363f-9562-a6322f46f01e/B080A97CCC049987852571620072F7F5-unicef-gen-may06.pdf -->}} <!-- Also available in other lanugages at https://www.unscn.org/web/archives_resources/html/resource_000380.html --></ref> [[Malnutrition]] and its consequences are large contributors to deaths, physical deformities, and disabilities worldwide.<ref name="Essential Nutrition Actions">{{cite web | publisher=World Health Organization | year=2013 | title=Essential Nutrition Actions: Improving maternal, newborn, infant and young child health and nutrition | location=Washington, DC | url=http://www.who.int/nutrition/publications/infantfeeding/essential_nutrition_actions/en/index.html | archive-url=https://web.archive.org/web/20130612230031/http://www.who.int/nutrition/publications/infantfeeding/essential_nutrition_actions/en/index.html | archive-date=2013-06-12}}</ref> Good nutrition is necessary for children to grow physically and mentally, and for normal human biological development.<ref name="Progress for Children" />
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== Recommended Dietary Allowances ==
The Recommended Dietary Allowances (RDAs) are scientifically determined levels of essential nutrient intake, deemed sufficient by the Food and Nutrition Board to meet the nutritional needs of nearly all healthy individuals.

The first [[RDA (nutrition)|RDAs]] were published in 1943, during World War II, with the aim of setting standards for optimal nutrition. The initial editions outlined daily nutrient recommendations for various age groups, reflecting the latest scientific insights at the time (NRC, 1943). The history and evolution of the RDAs have been extensively detailed by the chair of the first Committee on Recommended Dietary Allowances (Roberts, 1958). Over the years, the RDAs have been periodically updated, with the current version being the tenth edition.<ref name="allowances-1989">{{cite book | editor-last1=Havel | editor-first1=Richard J. | editor-last2=Calloway | editor-first2=Doris H. | editor-last3=Gussow | editor-first3=Joan D. | editor-last4=Mertz | editor-first4=Walter | editor-last5=Nesheim | editor-first5=Malden C. | date=February 1989 | chapter=Definition and applications | pages=10–23 | chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK234926/ | title=Recommended dietary allowances | language=en | edition=10th | publication-place=Washington, DC | publisher=National Academies Press | isbn=978-0-309-04041-9 | oclc=970496005 | doi=10.17226/1349 | pmid=25144070 | url=<!-- https://www.ncbi.nlm.nih.gov/books/NBK234932/ --> https://www.ncbi.nlm.nih.gov/books/NBK234932/pdf/Bookshelf_NBK234932.pdf#page=23}}</ref>

Originally intended to address nutrition issues related to national defense, the RDAs now serve multiple roles, including guiding food supply planning for population groups, interpreting dietary intake data, establishing standards for food assistance programs, assessing the nutritional adequacy of food supplies, designing nutrition education initiatives, aiding in the development of new food products, and setting guidelines for food labeling. However, the data underpinning these nutrient requirement estimates are often limited.<ref name="allowances-1989" />

The nutritional requirements system adopted by the United States and Canada refers to [[Dietary Reference Intake]] (DRI). The DRI is a set of nutritional guidelines developed by the National Academy of Medicine (NAM), part of the National Academies in the United States. Established in 1997, the DRI was created to expand upon the previous standards known as the Recommended Dietary Allowances (RDAs). Unlike the RDAs, the DRI encompasses a broader range of nutritional recommendations. The DRI values are distinct from those found on food and dietary supplement labels in the U.S. and Canada, which use Reference Daily Intakes (RDIs) and Daily Values (%). These labeling standards were originally based on RDAs from 1968 but were updated in 2016.<ref>{{Cite book | url=http://www.nap.edu/catalog/9956 | title=Dietary Reference Intakes: Applications in Dietary Assessment | date=2000-04-30 | publisher=National Academies Press | isbn=978-0-309-07183-3 | location=Washington, D.C. | doi=10.17226/9956 | pmid=25057725 | author1=Institute of Medicine (US) Subcommittee on Interpretation and Uses of Dietary Reference Intakes}}</ref>

[[Dietary Reference Value]]s (DRVs) represent the nutritional standards set by the United Kingdom's Department of Health and the European Food Safety Authority ([[EFSA]]) for assessing and planning dietary intakes. The UK's Department of Health introduced these guidelines in 1991 with the publication of ''Dietary Reference Values for Food Energy and Nutrients for the United Kingdom''. This document provides recommended nutrient intakes for the [[UK]] population, offering a framework for ensuring adequate nutrition.<ref name="powers-2021">{{Cite journal | last=Powers | first=Hilary J. | date=August 2021 | title=Approaches to setting dietary reference values for micronutrients, and translation into recommendations | url=https://www.cambridge.org/core/product/identifier/S0029665121000562/type/journal_article | journal=Proceedings of the Nutrition Society | language=en | volume=80 | issue=3 | pages=365–372 | doi=10.1017/S0029665121000562 | pmid=33663636 | issn=0029-6651}}</ref>

DRVs are categorized into three main types: Reference Nutrient Intake (RNI), which covers the nutritional needs of 95% of the population; Estimated Average Requirement (EAR), meeting the needs of 50%; and Lower Recommended Nutritional Intake (LRNI), which addresses the requirements of 5% of the population. These categories help to tailor dietary recommendations to different segments of the population, ensuring a more [[personalized]] approach to nutrition.<ref name="powers-2021" />

== Nutrients ==
{{Main|Nutrient}}

The seven major classes of nutrients are carbohydrates, [[fat]]s, [[dietary fiber|fiber]], [[dietary minerals|minerals]], [[protein]]s, [[vitamin]]s, and water.<ref name=WHO2004 /> Nutrients can be grouped as either [[macronutrients]] or [[micronutrients]] (needed in small quantities). Carbohydrates, fats, and proteins are macronutrients, and provide energy.<ref name=WHO2004 /> Water and fiber are macronutrients, but do not provide energy. The micronutrients are minerals and vitamins.<ref name=WHO2004>{{cite book | last1=World Health Organization, Food and Agricultural Organization of the United Nations | title=Vitamin and mineral requirements in human nutrition | date=2004 | publisher=World Health Organization | location=Geneva [u.a.] | isbn=978-9241546126 | edition=2. | url=https://www.who.int/nutrition/publications/micronutrients/9241546123/en/ | archive-url=https://web.archive.org/web/20121212005813/http://www.who.int/nutrition/publications/micronutrients/9241546123/en/ | url-status=dead | archive-date=12 December 2012}}</ref>

The macronutrients (excluding fiber and water) provide structural material (amino acids from which proteins are built, and lipids from which cell membranes and some signaling molecules are built), and [[Bioenergetics|energy]]. Some of the structural material can also be used to generate energy internally, and in either case it is measured in [[joule]]s or [[calorie|kilocalories]] (often called "Calories" and written with a capital 'C' to distinguish them from little 'c' calories). Carbohydrates and proteins provide 17&nbsp;kJ approximately (4&nbsp;kcal) of energy per gram, while fats provide 37&nbsp;kJ (9&nbsp;kcal) per gram.<ref name=Stryer>{{cite book | vauthors=Berg J, Tymoczko JL, Stryer L | title=Biochemistry | publisher=W.H. Freeman | edition=5th | location=San Francisco | year=2002 | isbn=978-0-7167-4684-3 | page=603}}</ref> However, the net energy derived from the macronutrients depends on such factors as absorption and digestive effort, which vary substantially from instance to instance.

Vitamins, minerals, fiber,<ref>{{cite web | url=http://www.webmd.com/food-recipes/features/get-the-facts-on-fiber | title=Get the Facts on Fiber | website=webmd.com | access-date=2020-01-04 | archive-date=2022-05-19 | archive-url=https://web.archive.org/web/20220519100104/https://www.webmd.com/food-recipes/features/get-the-facts-on-fiber | url-status=live}}</ref> and water do not provide energy, but are required for other reasons. A third class of dietary material, fiber (i.e., nondigestible material such as cellulose), seems also to be required, for both mechanical and biochemical reasons, though the exact reasons remain unclear. For all age groups, males on average need to consume higher amounts of macronutrients than females. In general, intakes increase with age until the second or third decade of life.<ref>{{Cite web | url=http://www.abs.gov.au/ausstats/abs@.nsf/Lookup/95E87FE64B144FA3CA2568A9001393C0 | title=National Nutrition Survey: Nutrient Intakes and Physical Measurements | date=1995 | website=Australian Bureau of Statistics | access-date=2015-04-02 | archive-date=2023-01-09 | archive-url=https://web.archive.org/web/20230109225431/https://www.abs.gov.au/ausstats/abs%40.nsf/Lookup/95E87FE64B144FA3CA2568A9001393C0 | url-status=live}}</ref>

Some nutrients can be stored&nbsp;– the fat-soluble vitamins&nbsp;– while others are required more or less continuously. Poor health can be caused by a lack of required nutrients, or for some vitamins and minerals, too much of a required nutrient. ''Essential'' nutrients cannot be synthesized by the body, and must be obtained from food.

Molecules of carbohydrates and fats consist of carbon, hydrogen, and oxygen atoms. Carbohydrates range from simple [[monosaccharides]] (glucose, fructose, galactose) to complex [[polysaccharides]] (starch, glycogen). Fats are [[triglyceride]]s, made of assorted [[fatty acid]] [[monomers]] bound to a [[glycerol]] backbone. Some fatty acids, but not all, are [[essential fatty acids|essential]] in the diet: they cannot be synthesized in the body. Protein molecules contain nitrogen atoms in addition to carbon, oxygen, and hydrogen.<ref name=Nelson2005>{{cite book | vauthors=Nelson DL, Cox MM | year=2005 | title=Lehninger's Principles of Biochemistry | edition=4th | publisher=W. H. Freeman and Company | location=New York, New York}}</ref> The fundamental components of protein are nitrogen-containing [[amino acids]], some of which are [[essential amino acids|essential]] in the sense that humans cannot make them internally. Some of the amino acids can be converted (with the expenditure of energy) to glucose and can be used for energy production just as ordinary glucose, in a process known as [[gluconeogenesis]]. By breaking down existing protein, some glucose can be produced internally; the remaining amino acids are discarded, primarily as urea in urine. This occurs naturally when [[atrophy]] takes place, or during periods of starvation.<ref>"Biodegradable Polymers: An Overview." ''Encyclopedia'', n.d. Accessed April 23, 2025.</ref>


The list of nutrients that people are known to require is, in the words of [[Marion Nestle]], "almost certainly incomplete".<ref>{{cite book | author=Nestle, Marion | author-link=Marion Nestle | title=Food Politics: How the Food Industry Influences Nutrition and Health | publisher=University of California Press | page=413 | isbn=978-0-520-27596-6 | year=2013 | orig-year=2002}}</ref>

=== Carbohydrates ===
{{Main|Carbohydrate}}

[[File:GrainProducts.jpg|thumb|upright|[[cereal|Grain]] products: rich sources of complex and simple carbohydrates]]

Carbohydrates may be classified as [[monosaccharide]]s, [[disaccharide]]s or [[polysaccharide]]s depending on the number of monomer (sugar) units they contain. They are a diverse group of substances, with a range of chemical, physical and physiological properties.<ref>{{cite journal | vauthors=Cummings JH, Stephen AM | title=Carbohydrate terminology and classification | journal=European Journal of Clinical Nutrition | volume=61 | pages=S5-18 | date=December 2007 | issue=Suppl 1 | pmid=17992187 | doi=10.1038/sj.ejcn.1602936 | s2cid=3330936 | url=http://www.nature.com.ipacez.nd.edu.au/ejcn/journal/v61/n1s/pdf/1602936a.pdf}}{{dead link|date=May 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> They make up a large part of foods such as [[rice]], [[noodles]], [[bread]], and other [[grain]]-based products,<ref>{{cite web | url=http://www.carb-counter.net/breads/2320 | title=Grams of Carbohydrates in White Bread – Carb Counter | website=www.carb-counter.net | access-date=18 March 2016 | archive-date=31 May 2016 | archive-url=https://web.archive.org/web/20160531092114/http://www.carb-counter.net/breads/2320 | url-status=live}}</ref><ref>{{cite web | url=http://www.amrice.com/6-4.cfm | title=American Rice, Inc. | website=www.amrice.com | access-date=18 March 2016 | archive-date=19 March 2016 | archive-url=https://web.archive.org/web/20160319144117/http://www.amrice.com/6-4.cfm | url-status=dead}}</ref> but they are not an essential nutrient, meaning a human does not need to eat carbohydrates.<ref>{{cite journal | vauthors=Westman EC | title=Is dietary carbohydrate essential for human nutrition? | journal=The American Journal of Clinical Nutrition | volume=75 | issue=5 | pages=951–3; author reply 953–4 | date=May 2002 | pmid=11976176 | doi=10.1093/ajcn/75.5.951a | doi-access=free}}</ref>

Monosaccharides contain one sugar unit, disaccharides two, and polysaccharides three or more. Monosaccharides include [[glucose]], [[fructose]] and [[galactose]].<ref>{{Cite web | url=http://healthyeating.sfgate.com/carbohydrates-contain-monosaccharides-1181.html | title=Carbohydrates That Contain Monosaccharides | website=Healthy eating | date=22 May 2012 | access-date=2015-04-17 | archive-date=2022-10-04 | archive-url=https://web.archive.org/web/20221004231344/https://healthyeating.sfgate.com/carbohydrates-contain-monosaccharides-1181.html | url-status=live}}</ref> Disaccharides include [[sucrose]], [[lactose]], and [[maltose]]; purified [[sucrose]], for instance, is used as table sugar.<ref>{{Cite journal | title=Principles of human nutrition | date=2015 | journal=Medicine | doi=10.1016/j.mpmed.2014.11.009 | volume=43 | issue=2 | pages=61–65 | last1=Lean | first1=Michael E.J. | s2cid=220865321}}</ref> Polysaccharides, which include [[starch]] and [[glycogen]], are often referred to as 'complex' carbohydrates because they are typically long multiple-branched chains of sugar units.

Traditionally, simple carbohydrates were believed to be absorbed quickly, and therefore raise blood-glucose levels more rapidly than complex carbohydrates. This is inaccurate.<ref>{{cite book | last=Otto | first=H | title=Diabetik Bei Diabetus Mellitus | year=1973 | publisher=Verlag Hans Huber | location=Bern}}</ref><ref>{{cite journal | last=Crapo | first=P | author2=Reaven, Olefsky | journal=Diabetes | year=1977 | volume=26 | pages=1178–83 | doi=10.2337/diabetes.26.12.1178 | pmid=590639 | title=Postprandial plasma-glucose and -insulin responses to different complex carbohydrates | issue=12}}</ref><ref>{{cite journal | last=Crapo | first=P | author2=Kolterman, Waldeck | author3=Reaven, Olefsky | journal=Am J Clin Nutr | year=1980 | volume=33 | pages=1723–28 | pmid=6996472 | title=Postprandial hormonal responses to different types of complex carbohydrate in individuals with impaired glucose tolerance | issue=8 | doi=10.1093/ajcn/33.8.1723}}</ref><ref>{{cite journal | last=Jenkins | first=David | author2=Jenkins, Alexandra L. | author3=Wolever, Thomas M.S. | author4=Thompson, Lilian H. | author5=Rao, A. Venkat | doi=10.1111/j.1753-4887.1986.tb07585.x | pmid=3703387 | title=Simple and complex carbohydrates | journal=Nutrition Reviews | date=February 1986 | volume=44 | issue=2 | pages=44–49}}</ref> Some simple carbohydrates (e.g., fructose) follow different metabolic pathways (e.g., [[fructolysis]]) that result in only a partial [[catabolism]] to glucose, while, in essence, many complex carbohydrates may be digested at the same rate as simple carbohydrates.<ref>{{cite web | title=The Nutrition Source: Carbohydrates | url=http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/carbohydrates/index.html | publisher=Harvard School of Public Health | access-date=7 July 2011 | archive-date=7 July 2011 | archive-url=https://web.archive.org/web/20110707013735/http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/carbohydrates/index.html | url-status=live}}</ref> The [[World Health Organization]] recommends that added sugars should represent no more than 10% of total energy intake.<ref>[https://web.archive.org/web/20041204172930/http://whqlibdoc.who.int/trs/WHO_TRS_916.pdf "WHO Technical Report Series. Diet, nutrition and the prevention of chronic diseases."] Report of a Joint WHO/FAO Expert Consultation; Geneva 2003. Retrieved 7 March 2011</ref>

The most common plant carbohydrate nutrient {{ndash}} starch {{ndash}} varies in its absorption. Starches have been classified as rapidly digestible starch, slowly digestible starch and [[resistant starch]].<ref>{{cite journal | last1=Englyst | first1=K.N. | last2=Liu | first2=S. | last3=Englyst | first3=H.N. | title=Nutritional characterization and measurement of dietary carbohydrates | journal=Eur J Clin Nutr | date=2007 | volume=61 | issue=Suppl 1 | pages=S19-39 | doi=10.1038/sj.ejcn.1602937 | pmid=17992185 | s2cid=4218364}}</ref> Starches in plants are resistant to digestion (resistant starch), but cooking the starch in the presence of water can break down the starch granule and releases the glucose chains, making them more easily digestible by human digestive enzymes.<ref>{{cite journal | last1=Wang | first1=Yi | last2=Chen | first2=Long | last3=Yang | first3=Tianyi | last4=Ma | first4=Yun | last5=McClements | first5=David Julian | last6=Ren | first6=Fei | last7=Tian | first7=Yaoqi | last8=Jin | first8=Zhengyu | title=A review of structural transformations and properties changes in starches during thermal processing of foods | journal=Food Hydrocolloids | date=2020 | volume=113 | page=106543 | doi=10.1016/j.foodhyd.2020.106543 | s2cid=230574900 | url=http://www.sciencedirect.com/science/article/pii/S0268005X20329179}}</ref> Historically, food was less processed and starches were contained within the food matrix, making them less digestible.<ref>{{cite journal | last1=Chen | first1=Lying | last2=Liu | first2=Ruining | last3=Qin | first3=Chengyong | last4=Meng | first4=Yan | last5=Zhang | first5=Jie | last6=Wang | first6=Yun | last7=Xu | first7=Guifa | title=Sources and intake of resistant starch in the Chinese diet | journal=Asia Pac J Clin Nutr | date=2010 | volume=19 | issue=2 | pages=274–282 | doi=10.6133/apjcn.2010.19.2.18 | pmid=20460244 | url=http://dx.doi.org/10.6133/apjcn.2010.19.2.18 | access-date=2021-02-26 | archive-date=2023-01-24 | archive-url=https://web.archive.org/web/20230124005339/https://www.airitilibrary.com/Publication/alDetailedMesh?DocID=09647058-201005-201306110032-201306110032-274-282 | url-status=live}}</ref> Modern food processing has shifted carbohydrate consumption from less digestible and resistant starch to much more rapidly digestible starch.<ref name="Lockyer RS Review">{{cite journal | last1=Lockyer | first1=S. | last2=Nugent | first2=A.P. | title=Health effects of resistant starch | journal=Nutrition Bulletin | date=2017 | volume=42 | issue=1 | pages=10–41 | doi=10.1111/nbu.12244 | s2cid=89991088 | doi-access=free}}</ref><ref>{{cite book | last1=Birkett | first1=A.M. | last2=Brown | first2=I.L. | title=Chapter 4: Resistant Starch and Health. In Technology of Functional Cereal Products | date=2008 | publisher=Woodhead Publishing Ltd – CRC Press LLC | location=Boca Raton, FL | isbn=978-1-84569-177-6 | pages=63–85}}</ref> For instance, the resistant starch content of a traditional African diet was 38 grams/day.<ref>{{cite journal | last1=O'Keefe | first1=Stephen J.D. | last2=et | first2=al. | title=Fat, fibre and cancer risk in African Americans and rural Africans | journal=Nat Commun | date=2015 | volume=6 | issue=1 | page=6342 | doi=10.1038/ncomms7342 | pmid=25919227 | pmc=4415091 | bibcode=2015NatCo...6.6342O}}</ref> The resistant starch consumption from countries with high starch intakes has been estimated to be 30-40 grams/day.<ref name="Baghurst Review">{{cite journal | last1=Baghurst | first1=P.A. | last2=Baghurst | first2=K.I. | last3=Record | first3=S.J. | title=Dietary fibre, non-starch polysaccharides and resistant starch – a review | journal=Food Australia | date=1996 | volume=48 | issue=3 | page=S1-S35 | url=http://agris.fao.org/agris-search/search.do?recordID=US201301518409 | access-date=2021-02-26 | archive-date=2022-01-19 | archive-url=https://web.archive.org/web/20220119195548/https://agris.fao.org/agris-search/search.do?recordID=US201301518409 | url-status=live}}</ref> In contrast, the average consumption of resistant starch in the United States was estimated to be 4.9 grams/day (range 2.8-7.9 grams of resistant starch/day).<ref name="Murphy RS Review">{{cite journal | last1=Murphy | first1=M.M. | last2=Douglass | first2=J.S. | last3=Birkett | first3=A. | title=Resistant starch intakes in the United States | journal=J Am Diet Assoc | date=2008 | volume=108 | issue=1 | pages=67–78 | doi=10.1016/j.jada.2007.10.012 | pmid=18155991}}</ref>

=== Fat ===
{{more medical citations needed|section|date=April 2019}}
{{Main|Fat}}

A molecule of dietary fat typically consists of several [[fatty acid]]s (containing long chains of carbon and hydrogen atoms), bonded to a [[glycerol]]. They are typically found as [[triglyceride]]s (three fatty acids attached to one glycerol backbone). Fats may be classified as [[saturated fat|saturated]] or [[unsaturated fat|unsaturated]] depending on the chemical structure of the fatty acids involved. Saturated fats have all of the [[carbon atoms]] in their fatty acid chains bonded to [[hydrogen atom]]s, whereas unsaturated fats have some of these carbon atoms [[Double bond|double-bonded]], so their molecules have relatively fewer hydrogen atoms than a saturated fatty acid of the same length. Unsaturated fats may be further classified as monounsaturated (one double-bond) or polyunsaturated (many double-bonds). Furthermore, depending on the location of the double-bond in the fatty acid chain, unsaturated fatty acids are classified as [[omega-3]] or [[omega-6]] fatty acids. [[Trans fat]]s are a type of unsaturated fat with ''trans''-isomer bonds; these are rare in nature and in foods from natural sources; they are typically created in an industrial process called (partial) [[hydrogenation]]. There are nine kilocalories in each gram of fat. Fatty acids such as [[conjugated linoleic acid]], [[catalpic acid]], [[eleostearic acid]] and [[punicic acid]], in addition to providing energy, represent potent immune modulatory molecules.<ref>{{cite book | author=National Research Council Committee on Diet and Health | editor-last1=Motulsky | editor-first1=Arno G. | editor-last2=Bierman | editor-first2=Edwin L. | editor-last3=Goodman | editor-first3=DeWitt S. | editor-last4=Mccormick | editor-first4=Donald B. | editor-last5=Arnaud | editor-first5=Claude D. | editor-last6=Iii | editor-first6=John C. Bailar | editor-last7=Blackburn | editor-first7=Henry | editor-last8=Bray | editor-first8=George A. | editor-last9=Carroll | editor-first9=Kenneth K. | editor-last10=Howe | editor-first10=Geoffrey R. | editor-last11=Hurley | editor-first11=Lucille S. | editor-last12=Kolonel | editor-first12=Laurence N. | editor-last13=Mcgill | editor-first13=Henry C. | editor-last14=Miller | editor-first14=Anthony B. | editor-last15=Page | editor-first15=Lot B. | editor-last16=Schieken | editor-first16=Richard M. | editor-last17=Shekelle | editor-first17=Richard B. | editor-last18=Tobian | editor-first18=Louis | editor-last19=Williams | editor-first19=Eleanor R. | display-editors=0 | date=1989 | chapter=Fats and Other Lipids | pages=159–258 | chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK218759/ | title=Diet and health: Implications for reducing chronic disease risk | url=https://www.ncbi.nlm.nih.gov/books/NBK218743/pdf/Bookshelf_NBK218743.pdf#page=176 | publication-place=Washington, DC | publisher=National Academies Press | language=en | doi=10.17226/1222 | doi-access=free | isbn=978-0-309-03994-9 | oclc=19457013 | pmid=25032333}} Also available from [https://nap.nationalacademies.org/read/1222/chapter/10 nationalacademies.org], with page numbers, but with Greek characters [[transliteration|transliterated]].</ref><ref>{{Cite journal | last1=Field | first1=Catherine J | last2=Robinson | first2=Lindsay | date=July 2019 | title=Dietary Fats | url=https://linkinghub.elsevier.com/retrieve/pii/S2161831322004136 | journal=Advances in Nutrition | language=en | volume=10 | issue=4 | pages=722–724 | doi=10.1093/advances/nmz052 | pmc=6628852 | pmid=31147674}}</ref>

Saturated fats (typically from animal sources) have been a staple in many world cultures for millennia. Unsaturated fats (e. g., vegetable oil) are considered healthier, while trans fats are to be avoided. Saturated and some trans fats are typically solid at room temperature (such as [[butter]] or [[lard]]), while unsaturated fats are typically liquids (such as [[olive oil]] or [[flaxseed oil]]). Trans fats are very rare in nature, and have been shown to be highly detrimental to human health, but have properties useful in the [[food processing]] industry, such as rancidity resistance.<ref>{{Cite journal | last=Klonoff | first=David C. | date=24 June 2016 | title=Replacements for Trans Fats—Will There Be an Oil Shortage? | pmc=2769584 | journal=Journal of Diabetes Science and Technology | language=en | volume=1 | issue=3 | pages=415–22 | doi=10.1177/193229680700100316 | pmid=19885099}}</ref>

==== Essential fatty acids ====
{{Main|Essential fatty acids}}
{{more medical citations needed|section|date=February 2020}}

Most fatty acids are non-essential, meaning the body can produce them as needed, generally from other fatty acids and always by expending energy to do so. However, in humans, at least two fatty acids are [[essential fatty acid|essential]] and must be included in the diet. An appropriate balance of essential fatty acids—[[omega-3]] and [[omega-6 fatty acid]]s—seems also important for health, although definitive experimental demonstration has been elusive. Both of these "omega" long-chain [[unsaturated fat|polyunsaturated fatty acids]] are [[substrate (biochemistry)|substrates]] for a class of [[eicosanoid]]s known as [[prostaglandin]]s, which have roles throughout the human body.<ref name="kaur-2014" />

The omega-3 [[eicosapentaenoic acid]] (EPA), which can be made in the human body from the omega-3 essential fatty acid [[alpha-linolenic acid]] (ALA), or taken in through marine food sources, serves as a building block for series 3 prostaglandins (e.g., weakly [[Inflammation|inflammatory]] PGE3). The [[Dihomo-γ-linolenic acid|omega-6 dihomo-gamma-linolenic acid]] (DGLA) serves as a building block for series 1 prostaglandins (e.g. anti-inflammatory PGE1), whereas [[arachidonic acid]] (AA) serves as a building block for series 2 [[prostaglandin]]s (e.g. pro-inflammatory PGE 2). Both DGLA and AA can be made from the omega-6 [[linoleic acid]] (LA) in the human body, or can be taken in directly through food.<ref name="kaur-2014">{{Cite journal | last1=Kaur | first1=Narinder | last2=Chugh | first2=Vishal | last3=Gupta | first3=Anil K. | date=October 2014 | title=Essential fatty acids as functional components of foods- a review | journal=Journal of Food Science and Technology | language=en | volume=51 | issue=10 | pages=2289–2303 | doi=10.1007/s13197-012-0677-0 | issn=0022-1155 | pmc=4190204 | pmid=25328170}}</ref> An appropriately balanced intake of omega-3 and omega-6 partly determines the relative production of different [[prostaglandin]]s. In industrialized societies, people typically consume large amounts of processed vegetable oils, which have reduced amounts of the essential fatty acids along with too much of omega-6 fatty acids relative to omega-3 fatty acids.<ref>{{cite journal | last1=Krupa | first1=Kristina N. | title=Omega-3 Fatty Acids | date=2024 | website=StatPearls | url=http://www.ncbi.nlm.nih.gov/books/NBK564314/ | access-date=2024-08-12 | place=Treasure Island (FL) | publisher=StatPearls Publishing | pmid=33231984 | last2=Fritz | first2=Kristina | last3=Parmar | first3=Mayur}}</ref>

The conversion rate of omega-6 DGLA to AA largely determines the production of the prostaglandins PGE1 and PGE2. Omega-3 EPA prevents AA from being released from membranes, thereby skewing prostaglandin balance away from pro-inflammatory PGE2 (made from AA) toward anti-inflammatory PGE1 (made from DGLA). The conversion (desaturation) of DGLA to AA is controlled by the enzyme [[desaturase|delta-5-desaturase]], which in turn is controlled by hormones such as [[insulin]] (up-regulation) and [[glucagon]] (down-regulation).

=== Fiber ===
{{Main|Dietary fiber}}
{{more medical citations needed|section|date=October 2024}}
Dietary fiber is a [[carbohydrate]], specifically a [[polysaccharide]], which is incompletely absorbed in humans and in some animals. Fiber slows down the absorption of sugar in the gut. The [[Microbiome of humans|microbiome]] converts fiber into signals that stimulate gut hormones, which in turn control how quickly the stomach empties, regulate blood sugar levels, and influence feelings of hunger. Like all carbohydrates, when fiber is digested, it can produce four [[calorie]]s (kilocalories) of energy per gram, but in most circumstances, it accounts for less than that because of its limited absorption and digestibility.

The two subcategories are ''insoluble'' and ''soluble'' fiber.

;Insoluble dietary fiber
:Includes [[cellulose]], a large carbohydrate polymer that is indigestible by humans, because humans do not have the required enzymes to break it down, and the human digestive system does not harbor enough of the types of microbes that can do so.
:Includes [[resistant starch]], an insoluble starch that resists digestion either because it is protected by a shell or food matrix (Type 1 resistant starch, RS1), maintains the natural starch granule (Type 2 resistant starch, RS2), is retrograded and partially crystallized (Type 3 resistant starch, RS3), has been chemically modified (Type 4 resistant starch, RS4) or has complexed with a lipid (Type 5 resistant starch, RS5).<ref name="Lockyer RS Review" /> Natural sources of resistant starch (RS1, RS2 and RS3) are fermented by the microbes in the human digestive system to produce short-chain fatty acids which are utilized as food for the colonic cells or absorbed.<ref name="Lockyer RS Review" />

;Soluble dietary fiber
:Comprises a variety of [[oligosaccharides]], [[waxes]], [[esters]], and other carbohydrates that dissolve or gelatinize in water. Many of these soluble fibers can be fermented or partially fermented by microbes in the human digestive system to produce short-chain fatty acids which are absorbed and therefore introduce some caloric content.<ref>{{Cite journal | last1=Hervik | first1=Astrid Kolderup | last2=Svihus | first2=Birger | date=2019 | title=The role of fiber in energy balance | journal=Journal of Nutrition and Metabolism | volume=2019 | pages=4983657 | doi=10.1155/2019/4983657 | issn=2090-0724 | pmc=6360548 | pmid=30805214 | doi-access=free}}</ref>

Whole grains, beans, and other [[legumes]], fruits (especially [[plum]]s, [[prune]]s, and [[fig]]s), and vegetables are good sources of dietary fiber. Fiber has three primary mechanisms, which in general determine their health impact: bulking, viscosity and fermentation.<ref name="Gallaher Fiber Review">{{cite book | last1=Gallaher | first1=Daniel D. | title=Chapter 8 – Dietary Fiber in Present Knowledge in Nutrition | date=2006 | publisher=ILSI Press | location=Washington DC | isbn=978-1-57881-199-1 | pages=102–110 | edition=Ninth Edition, Volume I}}</ref> Fiber provides bulk to the intestinal contents, and insoluble fiber facilitates [[peristalsis]]&nbsp;– the rhythmic muscular contractions of the intestines which move contents along the digestive tract. Some soluble and insoluble fibers produce a solution of high [[viscosity]]; this is essentially a gel, which slows the movement of food through the intestines. Fermentable fibers are used as food by the [[microbiome]], mildly increasing bulk, and producing [[short-chain fatty acid]]s and other metabolites, including vitamins, hormones, and glucose. One of these metabolites, [[butyrate]], is important as an energy source for colon cells, and may improve [[metabolic syndrome]].<ref>{{cite journal | last1=Bridgeman | first1=Stephanie C. | last2=Northrop | first2=Wendy | last3=Melton | first3=Phillip E. | last4=Ellison | first4=Gaewyn C. | last5=Newsholme | first5=Philip | last6=Mamotte | first6=Cyril D.S. | title=Butyrate generated by gut microbiota and its therapeutic role in metabolic syndrome | journal=Pharmacological Research | date=1 October 2020 | volume=160 | page=105174 | doi=10.1016/j.phrs.2020.105174 | pmid=32860943 | s2cid=221373075 | url=http://www.sciencedirect.com/science/article/pii/S1043661820314821}}</ref><ref>{{cite journal | last1=Wang | first1=Yong | last2=Chen | first2=Jing | last3=Song | first3=Ying-Han | last4=Zhao | first4=Rui | last5=Xia | first5=Lin | last6=Chen | first6=Yi | last7=Cui | first7=Ya-Ping | last8=Rao | first8=Zhi-Yong | last9=Zhou | first9=Yong |last10=Zhuang |first10=Wen | last11=Wu | first11=Xiao-Ting | title=Effects of the resistant starch on glucose, insulin, insulin resistance, and lipid parameters in overweight or obese adults: a systemic review and meta-analysis | journal=Nutrition & Diabetes | date=5 June 2019 | volume=9 | issue=1 | page=19 | doi=10.1038/s41387-019-0086-9 | pmid=31168050 | pmc=6551340 | url=https://doi.org/10.1038/s41387-019-0086-9 | access-date=22 February 2021 | archive-date=24 January 2023 | archive-url=https://web.archive.org/web/20230124005320/https://www.nature.com/articles/s41387-019-0086-9 | url-status=live}}</ref>

In 2016, the U.S. FDA approved a qualified [[health claim]] stating that resistant starch might reduce the risk of [[type 2 diabetes]], but with qualifying language for product labels that only limited scientific evidence exists to support this claim. The FDA requires specific labeling language, such as the guideline concerning resistant starch: "High-amylose maize resistant starch may reduce the risk of type 2 diabetes. FDA has concluded that there is limited scientific evidence for this claim."<ref name="FDA approved health claim RS2 resistant starch">{{cite web | last1=Balentine | first1=Douglas | title=Letter announcing decision for a health claim for high-amylose maize starch (containing type-2 resistant starch) and reduced risk of type 2 diabetes mellitus | url=https://www.regulations.gov/docket?D=FDA-2015-Q-2352 | website=www.regulations.gov | publisher=U.S. Food and Drug Administration | access-date=16 December 2016 | archive-date=20 December 2016 | archive-url=https://web.archive.org/web/20161220200555/https://www.regulations.gov/docket?D=FDA-2015-Q-2352 | url-status=live}}</ref>

=== Amino acids ===
[[File:Myoglobin.png|thumb|right|Proteins are chains of amino acids found in many nutritious foods. Pictured above is a computer rendering of [[myoglobin]], a protein found in muscles.]]
{{further|Protein (nutrient)|Protein quality|Amino acid score}}

Proteins are the basis of many animal body structures (e.g. muscles, skin, and hair) and form the [[enzyme]]s that control chemical reactions throughout the body. Each protein molecule is composed of [[amino acids]] which contain nitrogen and sometimes sulphur (these components are responsible for the distinctive smell of burning protein, such as the keratin in hair). The body requires amino acids to produce new proteins (protein retention) and to replace damaged proteins (maintenance). Amino acids are soluble in the digestive juices within the small intestine, where they are absorbed into the blood. Once absorbed, they cannot be stored in the body, so they are either metabolized as required or excreted in the urine.{{medical citation needed|date=July 2015}} Proteins consist of amino acids in different proportions. The most important aspect and defining characteristic of protein from a nutritional standpoint is its amino acid composition.<ref name="DRI">Dietary Reference Intakes: The Essential Guide to Nutrient Requirements, published by the Institute of Medicine's Food and Nutrition Board, currently available online at {{cite web | url=http://fnic.nal.usda.gov/dietary-guidance/dietary-reference-intakes/dri-reports | title=DRI Reports {{pipe}} Food and Nutrition Information Center | access-date=14 July 2014 | url-status=dead | archive-url=https://web.archive.org/web/20140705140516/http://fnic.nal.usda.gov/dietary-guidance/dietary-reference-intakes/dri-reports | archive-date=5 July 2014}}</ref>

For all animals, some amino acids are ''[[essential amino acid|essential]]'' (an animal cannot produce them internally so they must be eaten) and some are ''[[non-essential amino acid|non-essential]]'' (the animal can produce them from other nitrogen-containing compounds). About twenty amino acids are found in the human body, and about ten of these are essential. The synthesis of some amino acids can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress, and those are called conditionally essential.<ref name="DRI" />

A diet that contains adequate amounts of amino acids (especially those that are essential) is particularly important in some situations: during early development and maturation, pregnancy, lactation, or injury (a burn, for instance). A [[complete protein]] source contains all the essential amino acids; an incomplete protein source lacks one or more of the essential amino acids. It is possible with [[protein combination]]s of two incomplete protein sources (e.g., rice and beans) to make a complete protein source, and characteristic combinations are the basis of distinct cultural cooking traditions. However, complementary sources of protein do not need to be eaten at the same meal to be used together by the body.<ref>{{cite journal | author=American Dietetic Association | title=Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets | journal=Journal of the American Dental Association | year=2003 | volume=103 | issue=6 | pages=748–65 | pmid=12778049 | doi=10.1053/jada.2003.50142 | last2=Dietitians Of | first2=Canada}}</ref> Excess amino acids from protein can be converted into glucose and used for fuel through a process called [[gluconeogenesis]].

There is an ongoing debate about the differences in nutritional quality and adequacy of protein from [[Veganism|vegan]], [[Vegetarianism|vegetarian]] and animal sources, though many studies and institutions have found that a well-planned vegan or vegetarian diet contains enough high-quality protein to support the protein requirements of both sedentary and active people at all stages of life.<ref>{{cite journal | vauthors=Alexandrov NV, Eelderink C, Singh-Povel CM, Navis GJ, Bakker SJ, Corpeleijn E | title=Dietary Protein Sources and Muscle Mass over the Life Course: The Lifelines Cohort Study | journal=Nutrients | volume=10 | issue=10 | pages=1471 | date=October 2018 | pmid=30308987 | pmc=6212815 | doi=10.3390/nu10101471 | doi-access=free}}</ref><ref>{{cite web | url=https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/ | title=Protein | date=18 September 2012 | website=The Nutrition Source | language=en-us | access-date=31 October 2019 | archive-date=27 October 2019 | archive-url=https://web.archive.org/web/20191027201530/https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/ | url-status=live}}</ref><ref>{{cite journal | vauthors=Rogerson D | title=Vegan diets: practical advice for athletes and exercisers | journal=Journal of the International Society of Sports Nutrition | volume=14 | pages=36 | date=13 September 2017 | issue=1 | pmid=28924423 | pmc=5598028 | doi=10.1186/s12970-017-0192-9 | doi-access=free}}</ref><ref name="dinu">{{cite journal | vauthors=Dinu M, Abbate R, Gensini GF, Casini A, Sofi F | title=Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies | journal=Critical Reviews in Food Science and Nutrition | volume=57 | issue=17 | pages=3640–3649 | date=November 2017 | pmid=26853923 | doi=10.1080/10408398.2016.1138447 | url=https://flore.unifi.it/bitstream/2158/1079985/4/Vegetarian%2c%20vegan%20diets%20and%20multiple%20he...meta-analysis%20of%20observational%20studies.pdf | hdl=2158/1079985 | s2cid=10073754 | access-date=2018-08-02 | archive-date=2023-01-24 | archive-url=https://web.archive.org/web/20230124005332/https://flore.unifi.it/rm-password-login | url-status=live}}</ref>

=== Water ===
{{Main|Drinking water}}
[[File:TapWater-china.JPG|thumb|left|A manual [[water]] [[pump]] in [[China]]]]
Water is excreted from the body in multiple forms; including [[urine]] and [[Human feces|feces]], [[sweating]], and by [[water vapour]] in the exhaled breath. Therefore, it is necessary to adequately rehydrate to replace lost fluids.

Early recommendations for the quantity of water required for maintenance of good health suggested that six to eight glasses of water daily is the minimum to maintain proper [[Tissue hydration|hydration]].<ref>{{cite web | url=https://www.bbc.co.uk/health/healthy_living/nutrition/drinks_water.shtml | title=Healthy Water Living | publisher=BBC. Retrieved 1 February 2007 | archive-url=https://web.archive.org/web/20070101100025/http://www.bbc.co.uk/health/healthy_living/nutrition/drinks_water.shtml | archive-date=1 January 2007}}</ref> However, the notion that a person should consume eight glasses of water per day cannot be traced to a credible scientific source.<ref>{{cite journal | title="Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 × 8"? | journal=American Journal of Physiology. Regulatory, Integrative and Comparative Physiology | volume=283 | issue=5 | pages=R993–R1004 | doi=10.1152/ajpregu.00365.2002 | pmid=12376390 | year=2002 | last1=Valtin | first1=Heinz}}</ref> The original water intake recommendation in 1945 by the Food and Nutrition Board of the [[United States National Research Council|National Research Council]] read: "An ordinary standard for diverse persons is 1 milliliter for each calorie of food. Most of this quantity is contained in prepared foods."<ref>Food and Nutrition Board, National Academy of Sciences. Recommended Dietary Allowances, revised 1945. National Research Council, Reprint and Circular Series, No. 122, 1945 (Aug), pp. 3–18.</ref> More recent comparisons of well-known recommendations on fluid intake have revealed large discrepancies in the volumes of water we need to consume for good health.<ref name="Le Bellego">{{cite journal | vauthors=Le Bellego L, Jean C, Jiménez L, Magnani C, Tang W, Boutrolle I | title=Understanding fluid consumption patterns to improve healthy hydration | journal=Nutr Today | year=2010 | volume=45 | issue=6 | pages=S22–S26 | doi=10.1097/NT.0b013e3181fe4314 | s2cid=76128311 | doi-access=free}}</ref> Therefore, to help standardize guidelines, recommendations for water consumption are included in two recent [[European Food Safety Authority]] (EFSA) documents (2010): (i) Food-based dietary guidelines and (ii) Dietary reference values for water or adequate daily intakes (ADI).<ref name="Scientific Opinion on Dietary Reference Values for water">{{cite journal | author=EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) | doi=10.2903/j.efsa.2010.1459 | title=Scientific Opinion on Dietary Reference Values for Water | journal=EFSA Journal | year=2010 | volume=8 | issue=3 | page=1459 | s2cid=79245852 | url=http://orbit.dtu.dk/files/6350877/5.Scientific.pdf | archive-url=https://web.archive.org/web/20170922040703/http://orbit.dtu.dk/files/6350877/5.Scientific.pdf | archive-date=2017-09-22 | url-status=live}}{{open access}}</ref> These specifications were provided by calculating adequate intakes from measured intakes in populations of individuals with "desirable osmolarity values of urine and desirable water volumes per energy unit consumed".<ref name="Scientific Opinion on Dietary Reference Values for water" />

For healthful hydration, the current EFSA guidelines recommend total water intakes of 2.0 L/day for adult females and 2.5 L/day for adult males. These reference values include water from drinking water, other beverages, and from food. About 80% of our daily water requirement comes from the beverages we drink, with the remaining 20% coming from food.<ref>{{cite journal | last1=Armstrong | first1=Lawrence E. | last2=Pumerantz | first2=Amy C. | last3=Roti | first3=Melissa W. | last4=Judelson | first4=Daniel A. | last5=Watson | first5=Greig | last6=Dias | first6=Joao C. | last7=Sökmen | first7=Bülent | last8=Casa | first8=Douglas J. | last9=Maresh | first9=Carl M. | last10=Lieberman | first10=Harris | last11=Kellogg | first11=Mark | year=2005 | title=Fluid, electrolyte, and renal indices of hydration during 11 days of controlled caffeine consumption | journal=International Journal of Sport Nutrition and Exercise Metabolism | publication-place=Champaign, Illinois | publisher=Human Kinetics Publishers | volume=15 | issue=3 | pages=252–265 | issn=1526-484X | pmid=16131696 | doi=10.1123/ijsnem.15.3.252 | url=https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=640f49f096f9a01e2c3ef103945a39830a12cd5c <!-- https://www.researchgate.net/profile/Mark-Kellogg/publication/7628664_Fluid_electrolyte_and_renal_indices_of_hydration_during_11_days_of_controlled_caffeine_consumption/links/09e4150bf9c40a8468000000/Fluid-electrolyte-and-renal-indices-of-hydration-during-11-days-of-controlled-caffeine-consumption.pdf -->}}</ref> Water content varies depending on the type of food consumed, with fruit and vegetables containing more than cereals, for example.<ref name="FAO">[http://www.fao.org/docrep/003/x9892e/x9892e00.htm "FAO Corporate Document Repository. Food Balance Sheets- A Handbook."] {{Webarchive|url=https://web.archive.org/web/20190217073049/http://www.fao.org/docrep/003/X9892E/X9892E00.HTM |date=2019-02-17 }} Retrieved 7 March 2011</ref> These values are estimated using country-specific food balance sheets published by the Food and Agriculture Organisation of the United Nations.<ref name="FAO" />

The EFSA panel also determined intakes for different populations. Recommended intake volumes in the elderly are the same as for adults as despite lower energy consumption, the water requirement of this group is increased due to a reduction in renal concentrating capacity.<ref name="Scientific Opinion on Dietary Reference Values for water" /> [[Pregnant]] and [[breastfeeding]] women require additional fluids to stay hydrated. The EFSA panel proposes that pregnant women should consume the same volume of water as non-pregnant women, plus an increase in proportion to the higher energy requirement, equal to 300 mL/day.<ref name="Scientific Opinion on Dietary Reference Values for water" /> To compensate for additional fluid output, breastfeeding women require an additional 700 mL/day above the recommended intake values for non-lactating women. Dehydration and over-hydration&nbsp;– too little and too much water, respectively&nbsp;– can have harmful consequences. Drinking too much water is one of the possible causes of [[hyponatremia]], i.e., low serum sodium.<ref name="Scientific Opinion on Dietary Reference Values for water" /><ref>{{cite journal | pmc=1770067 | title=Fatal water intoxication | journal=Journal of Clinical Pathology | date=October 2003 | pmid=14514793 | volume=56 | issue=10 | vauthors=Farrell DJ, Bower L | pages=803–04 | doi=10.1136/jcp.56.10.803-a}}</ref>

=== Minerals ===
{{right|{{Periodic table (for higher organisms)}}}}
{{Main|Mineral (nutrient)|Composition of the human body}}
Dietary minerals are [[inorganic compounds|inorganic]] [[chemical element]]s required by living organisms,<ref name="Mitchell, Dakota and Haroun, Lee 2012 279">{{cite book | author1=Mitchell, Dakota | author2=Haroun, Lee | title=Introduction to Health Care | year=2012 | edition=3 | publisher=Delmar Cengage | isbn=978-1-4354-8755-0 | page=279}}</ref> other than the four elements [[carbon]], [[hydrogen]], [[nitrogen]], and [[oxygen]] that are present in nearly all [[organic chemistry|organic molecules]]. Some have roles as [[Cofactor (biochemistry)|cofactors]], while others are [[electrolyte]]s.<ref>{{cite book | author1=Nelson, D.L. | author2=Cox, M.M. | title=Lehninger Principles of Biochemistry | edition=3rd | publisher=Worth Publishing | location=New York | year=2000 | isbn=978-1-57259-153-0}}</ref> The term "mineral" is archaic, since the intent is to describe simply the less common elements in the diet. Some are heavier than the four just mentioned – including several [[metals]], which often occur as ions in the body. Some dietitians recommend that these be supplied from foods in which they occur naturally, or at least as complex compounds, or sometimes even from natural inorganic sources (such as [[calcium carbonate]] from ground [[oyster]] shells). Some are absorbed much more readily in the ionic forms found in such sources. On the other hand, minerals are often artificially added to the diet as supplements; the most well-known is likely iodine in [[iodized salt]] which prevents [[goiter]].<ref>{{Cite journal | last1=Datta | first1=Mridul | last2=Vitolins | first2=Mara Z. | date=2016-10-02 | title=Food Fortification and Supplement Use – Are there Health Implications? | journal=Critical Reviews in Food Science and Nutrition | volume=56 | issue=13 | pages=2149–2159 | doi=10.1080/10408398.2013.818527 | issn=1040-8398 | pmc=4692722 | pmid=25036360}}</ref>

==== Macrominerals ====
Elements with recommended dietary allowance ([[Recommended Dietary Allowance|RDA]]) greater than 150&nbsp;mg/day are, in alphabetical order:
*[[Calcium]] (Ca<sup>2+</sup>) is vital to the health of the muscular, circulatory, and digestive systems; is indispensable to the building of bone; and supports the synthesis and function of blood cells. For example, calcium is used to regulate the contraction of muscles, nerve conduction, and the clotting of blood. It can play this role because the Ca<sup>2+</sup> ion forms stable [[coordination complex]]es with many organic compounds, especially [[protein]]s; it also forms compounds with a wide range of solubility, enabling the formation of the [[skeleton]].<ref>{{Cite web | url=https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/ | title=Office of Dietary Supplements – Calcium | website=ods.od.nih.gov | language=en | access-date=31 October 2019 | archive-date=17 March 2018 | archive-url=https://web.archive.org/web/20180317073525/https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/ | url-status=live}}</ref> Food sources include yogurt, milk, cheese, leafy greens, tofu, and fortified beverages.<ref>{{Cite web |title=Food Sources of Calcium {{!}} Dietary Guidelines for Americans |url=https://www.dietaryguidelines.gov/food-sources-calcium |access-date=2024-10-05 |website=www.dietaryguidelines.gov}}</ref>
*[[Chlorine]] as [[chloride]] ions; electrolyte; see sodium, below.
* [[Magnesium]], required for processing [[Adenosine triphosphate|ATP]] and related reactions (builds bone, causes strong [[peristalsis]], increases flexibility, increases alkalinity). Approximately 50% is in bone, the remaining 50% is almost all inside body cells, with only about 1% located in extracellular fluid. Food sources include oats, buckwheat, tofu, nuts, caviar, green leafy vegetables, legumes, and chocolate.<ref name="mahan">{{cite book | title=Krausw's Food and the Nutrition Care Process | edition=13th | publisher=Elsevier | location=St. Louis | year=2012 | isbn=978-1-4377-2233-8 | author1=L. Kathleen Mahan | author2=Janice L. Raymond | author3=Sylvia Escott-Stump}}</ref><ref name="USDA DB">{{Cite web | url=https://fdc.nal.usda.gov/ | title=USDA National Nutrient Database for Standard Reference, SR26, 2013 | access-date=2022-10-19 | archive-date=2023-01-15 | archive-url=https://web.archive.org/web/20230115162310/http://fdc.nal.usda.gov/ | url-status=live}}</ref>
* [[Phosphorus]], required component of bones; essential for energy processing.<ref>{{cite book | author=D. E. C. Corbridge | title=Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology | edition=5th | publisher=Elsevier | location=Amsterdam | year=1995 | isbn=978-0-444-89307-9}}</ref> Approximately 80% is found in the inorganic portion of bones and teeth. Phosphorus is a component of every cell, as well as important metabolites, including DNA, RNA, ATP, and phospholipids. Also important in pH regulation. It is an important electrolyte in the form of [[phosphate]].<ref>{{Cite web | url=https://www.msdmanuals.com/en-in/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/overview-of-disorders-of-phosphate-concentration | title=Overview of Disorders of Phosphate Concentration – Endocrine and Metabolic Disorders | website=MSD Manual Professional Edition | language=en-IN | access-date=31 October 2019 | archive-date=5 August 2019 | archive-url=https://web.archive.org/web/20190805043750/https://www.msdmanuals.com/en-in/professional/endocrine-and-metabolic-disorders/electrolyte-disorders/overview-of-disorders-of-phosphate-concentration | url-status=live}}</ref> Food sources include cheese, egg yolk, milk, meat, fish, poultry, whole-grain cereals, and many others.<ref name="mahan" />
* [[Potassium]], an electrolyte (heart and nerve function). With sodium, potassium is involved in maintaining normal water balance, osmotic equilibrium, and acid-base balance. In addition to calcium, it is important in the regulation of neuromuscular activity. Food sources include bananas, avocados, nuts, vegetables, potatoes, legumes, fish, and mushrooms.<ref name="USDA DB" />
* [[Sodium]], a common food ingredient and [[electrolyte]], found in most foods and manufactured consumer products, typically as [[sodium chloride]] (salt). Excessive sodium consumption can deplete [[calcium]] and [[magnesium]].<ref>{{Cite web | url=http://www.fao.org/docrep/004/Y2809E/y2809e0k.htm | title=Chapter 14. Magnesium | website=Food and Agriculture Organization of the United States | access-date=2020-01-03 | archive-date=2019-11-01 | archive-url=https://web.archive.org/web/20191101125852/http://www.fao.org/docrep/004/Y2809E/y2809e0k.htm | url-status=live}}</ref> Sodium has a role in the etiology of [[hypertension]] demonstrated from studies showing that a reduction of table salt intake may reduce blood pressure.<ref>{{Cite journal | last=Ha | first=Sung Kyu | date=1 June 2014 | title=Dietary salt intake and hypertension | pmc=4105387 | journal=Electrolytes & Blood Pressure | volume=12 | issue=1 | pages=7–18 | doi=10.5049/EBP.2014.12.1.7 | issn=1738-5997 | pmid=25061468}}</ref><ref>{{Cite journal | last1=Wang | first1=Miao | last2=Moran | first2=Andrew E. | last3=Liu | first3=Jing | last4=Qi | first4=Yue | last5=Xie | first5=Wuxiang | last6=Tzong | first6=Keane | last7=Zhao | first7=Dong | date=1 December 2015 | title=A Meta-Analysis of Effect of Dietary Salt Restriction on Blood Pressure in Chinese Adults | journal=Global Heart | volume=10 | issue=4 | pages=291–299.e6 | doi=10.1016/j.gheart.2014.10.009 | issn=2211-8179 | pmc=4529389 | pmid=26014655}}</ref>

==== Trace minerals ====
Many elements are required in smaller amounts (microgram quantities), usually because they play a [[catalytic]] role in [[enzymes]].<ref name=lipp>{{cite book | author1=Lippard, S. J. | author2=Berg, J. M. | title=Principles of Bioinorganic Chemistry | publisher=University Science Books | location=Mill Valley, CA | year=1994 | isbn=978-0-935702-73-6}}</ref> Some trace mineral elements (RDA < 200&nbsp;mg/day) are, in alphabetical order:{{medical citation needed|date=July 2015}}
* [[Cobalt]] as a component of the [[vitamin B12|vitamin B<sub>12</sub>]] family of [[coenzyme]]s
* [[Copper]] required component of many redox enzymes, including [[cytochrome c oxidase]] (see [[Copper in health]])
* [[Chromium]] required for sugar metabolism
* [[Iodine]] required not only for the biosynthesis of [[thyroxin]], but probably, for other important organs as breast, stomach, salivary glands, thymus etc. (see [[Iodine deficiency]]); for this reason iodine is needed in larger quantities than others in this list, and sometimes classified with the macrominerals;<ref>{{cite journal | vauthors=Kapil U | title=Health consequences of iodine deficiency | journal=Sultan Qaboos University Medical Journal | volume=7 | issue=3 | pages=267–72 | date=December 2007 | pmid=21748117 | pmc=3074887}}</ref> Nowadays it is most easily found in iodized salt, but there are also natural sources such as ''[[Kombu]]''.<ref>{{cite journal | vauthors=Zava TT, Zava DT | title=Assessment of Japanese iodine intake based on seaweed consumption in Japan: A literature-based analysis | journal=Thyroid Research | volume=4 | issue=1 | pages=14 | date=October 2011 | pmid=21975053 | pmc=3204293 | doi=10.1186/1756-6614-4-14 | doi-access=free}}</ref><ref>{{cite journal | last1=Yeh | first1=Tai Sheng | last2=Hung | first2=Nu Hui | last3=Lin | first3=Tzu Chun | date=1 June 2014 | title=Analysis of iodine content in seaweed by GC-ECD and estimation of iodine intake | journal=Journal of Food and Drug Analysis | volume=22 | issue=2 | pages=189–196 | doi=10.1016/j.jfda.2014.01.014 | issn=1021-9498 | doi-access=free | pmc=9359334}}</ref>
* [[Iron]] required for many enzymes, and for [[hemoglobin]] and some other proteins
* [[Manganese]] (processing of oxygen)
* [[Molybdenum]] required for [[xanthine oxidase]] and related oxidases
* [[Selenium]] required for [[peroxidase]] (antioxidant proteins)
* [[Zinc]] required for several enzymes such as [[carboxypeptidase]], [[Alcohol dehydrogenase#Human|liver alcohol dehydrogenase]], [[carbonic anhydrase]]

==== Ultratrace minerals ====
Ultratrace minerals are an as yet unproven aspect of human nutrition, and may be required at amounts measured in very low ranges of μg/day. Many [[ultratrace element]]s have been suggested as essential, but such claims have usually not been confirmed. Definitive evidence for efficacy comes from the characterization of a biomolecule containing the element with an identifiable and testable function. These include:<ref>{{cite journal | last=Nielsen | first=Forrest H. | date=1998 | title=Ultratrace elements in nutrition: Current knowledge and speculation | journal=The Journal of Trace Elements in Experimental Medicine | language=en | volume=11 | issue=2–3 | pages=251–274 | doi=10.1002/(SICI)1520-670X(1998)11:2/3<251::AID-JTRA15>3.0.CO;2-Q | issn=1520-670X}}</ref><ref>{{cite journal | vauthors=Nielsen FH | title=How should dietary guidance be given for mineral elements with beneficial actions or suspected of being essential? | journal=The Journal of Nutrition | volume=126 | issue=9 Suppl | pages=2377S–2385S | date=September 1996 | pmid=8811801 | doi=10.1093/jn/126.suppl_9.2377S | doi-access=free}}</ref>
* Bromine
* Arsenic
* Nickel
* Fluorine
* Boron
* Lithium
* Strontium
* Silicon
* Vanadium

=== Vitamins ===
{{Main|Vitamin}}

Except for [[vitamin D]], vitamins are essential nutrients,<ref name="Mitchell, Dakota and Haroun, Lee 2012 279" /> necessary in the diet for good health. Vitamin D can be synthesized in the skin in the presence of [[UVB radiation]]. (Many animal species can synthesize [[vitamin C]], but humans cannot.) Certain vitamin-like compounds that are recommended in the diet, such as [[carnitine]], are thought useful for survival and health, but these are not "essential" dietary nutrients because the human body has some capacity to produce them from other compounds. Moreover, thousands of different [[phytochemicals]] have recently been discovered in food (particularly in fresh vegetables), which may have desirable properties including [[antioxidant]] activity (see below); experimental demonstration has been suggestive but inconclusive. Other essential nutrients not classed as vitamins include [[essential amino acid]]s (see [[#Amino Acids|above]]), [[essential fatty acid]]s (see [[#Essential fatty acids|above]]), and the minerals discussed in the preceding section.{{medical citation needed|date=July 2015}}

Vitamin deficiencies may result in disease conditions: [[goiter]], [[scurvy]], [[osteoporosis]], impaired [[immune system]], disorders of cell [[metabolism]], certain forms of cancer, symptoms of premature [[aging]], and poor [[psychology|psychological health]] (including [[eating disorders]]), among many others.<ref>{{cite book | year=2005 | title=Modern Nutrition in Health and Disease | publisher=Lippincott Williams and Wilkins | isbn=978-0-7817-4133-0 | author=Shils}}</ref>

Excess levels of some vitamins are also dangerous to health. The Food and Nutrition Board of the Institute of Medicine has established Tolerable Upper Intake Levels (ULs) for seven vitamins.<ref>{{cite book | editor1=Institute of Medicine | editor-last2=Ross | editor-first2=A. Catharine | editor-last3=Taylor | editor-first3=Christine L. | editor-last4=Yaktine | editor-first4=Ann L. | editor-last5=Del Valle | editor-first5=Heather B. | date=30 March 2011 | title=Dietary reference intakes for calcium and vitamin D | publication-place=Washington, DC | publisher=National Academies Press | isbn=978-0-309-16394-1 | doi=10.17226/13050 | oclc=721907472 | pmid=21796828 | at=pp. [https://nap.nationalacademies.org/read/13050/chapter/24#1112 1112]-1113, Table: Dietary reference intakes (DRIs): Tolerable upper intake levels, vitamins | url=https://www.ncbi.nlm.nih.gov/books/NBK56068/table/summarytables.t7/?report=objectonly | archive-date=2022-06-29 | archive-url=https://web.archive.org/web/20220629190328/https://www.ncbi.nlm.nih.gov/books/NBK56068/table/summarytables.t7/?report=objectonly | url-status=live | author1=Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium | last2=Ross | first2=A. C. | last3=Taylor | first3=C. L. | last4=Yaktine | first4=A. L. | last5=Del Valle | first5=H. B. }}</ref>

== Malnutrition ==
{{Main|Malnutrition}}
The term malnutrition addresses 3 broad groups of conditions:
* Undernutrition, which includes wasting (low weight-for-height), stunting (low height-for-age) and underweight (low weight-for-age)
* Micronutrient-related malnutrition, which includes micronutrient deficiencies or insufficiencies (a lack of important vitamins and minerals) or micronutrient excess
* Overweight, obesity and diet-related noncommunicable diseases (such as heart disease, stroke, diabetes and some cancers).<ref>{{cite web | url=https://www.who.int/news-room/fact-sheets/detail/malnutrition | title=Malnutrition | website=www.who.int | access-date=2020-01-03 | archive-date=2022-07-16 | archive-url=https://web.archive.org/web/20220716200708/https://www.who.int/news-room/fact-sheets/detail/malnutrition | url-status=live}}</ref>

In developed countries, the diseases of malnutrition are most often associated with nutritional imbalances or excessive consumption; there are more people in the world who are malnourished due to excessive consumption. According to the United Nations [[World Health Organization]], the greatest challenge in developing nations today is not starvation, but insufficient nutrition&nbsp;– the lack of nutrients necessary for the growth and maintenance of vital functions. The causes of malnutrition are directly linked to inadequate macronutrient consumption and disease, and are indirectly linked to factors like "household food security, maternal and child care, health services, and the environment".<ref name="Essential Nutrition Actions" />

=== Insufficient ===
The U.S. Food and Nutrition Board sets Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamins and minerals. EARs and RDAs are part of [[Dietary Reference Intake]]s.<ref name="ods.od.nih.gov">[https://ods.od.nih.gov/Health_Information/Dietary_Reference_Intakes.aspx] {{Webarchive|url=https://web.archive.org/web/20200702082029/https://ods.od.nih.gov/Health_Information/Dietary_Reference_Intakes.aspx|date=2020-07-02}}
Nutrient recommendations: Dietary Reference Intakes (DRI).</ref> The DRI documents describe nutrient deficiency signs and symptoms.

=== Excessive ===
The U.S. Food and Nutrition Board sets Tolerable Upper Intake Levels (known as ULs) for vitamins and minerals when evidence is sufficient. ULs are set a safe fraction below amounts shown to cause health problems. ULs are part of [[Dietary Reference Intake]]s.<ref name="ods.od.nih.gov" /> The [[European Food Safety Authority]] also reviews the same safety questions and set its own ULs.<ref>{{cite report | author=[[Scientific Committee on Food]] | author2=Scientific Panel on Dietetic Products, Nutrition and Allergies | editor-last=Flynn | editor-first=Albert | display-editors=0 | date=February 2006 | title=Tolerable upper intake levels for vitamins and minerals | publication-place=Parma | publisher=European Food Safety Authority | isbn=978-92-9199-014-6 | oclc=123415533 | url=http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf | access-date=2020-01-03 | archive-date=2016-03-16 | archive-url=https://web.archive.org/web/20160316225123/http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf | url-status=live}}</ref>

=== Unbalanced ===
When too much of one or more nutrients is present in the diet to the exclusion of the proper amount of other nutrients, the diet is said to be unbalanced. High calorie food ingredients such as vegetable oils, sugar and alcohol are referred to as [[Empty calorie|"empty calories"]] because they displace from the diet foods that also contain protein, vitamins, minerals and fiber.<ref>{{cite web | title=What are empty calories? | website=USDA MyPlate 2011 | url=http://www.choosemyplate.gov/weight-management-calories/calories/empty-calories.html | access-date=20 October 2017 | url-status=dead | archive-url=https://web.archive.org/web/20140130125320/http://www.choosemyplate.gov/weight-management-calories/calories/empty-calories.html | archive-date=30 January 2014 | date=27 March 2015}}</ref>

=== Illnesses caused by underconsumption and overconsumption ===
{| class="wikitable"
|-
! Nutrients
! Deficiency
! Excess
|-
| colspan="3" style="background: #dd99cc; text-align: center;"| '''[[Macronutrient]]s'''
|-
| [[Food energy]]
| [[Starvation]], [[marasmus]]
| [[Obesity]], [[diabetes mellitus]], [[cardiovascular disease]]
|-
| [[Simple carbohydrate]]s
| None
| [[Obesity]], [[diabetes mellitus]], [[cardiovascular disease]]
|-
| [[Complex carbohydrate]]s
| None
| [[Obesity]], [[cardiovascular disease]] (high glycemic index foods)
|-
| [[Protein (nutrient)|Protein]]
| [[Kwashiorkor]]
| [[Protein poisoning]]
|-
| [[Saturated fat]]
| Low testosterone levels,<ref>{{cite web | url=http://deepfitness.com/705/The-Big-T-How-Your-Lifestyle-Influences-Your-Testosterone-Levels.aspx | title=The Big T: How Your Lifestyle Influences Your Testosterone Levels | publisher=Deepfitness.com | access-date=8 October 2013 | author=Berardi, John | url-status=dead | archive-url=https://archive.today/20120530054846/http://deepfitness.com/705/The-Big-T-How-Your-Lifestyle-Influences-Your-Testosterone-Levels.aspx | archive-date=30 May 2012}}</ref> vitamin deficiencies{{citation needed|date=January 2020}}
| [[Obesity]], [[cardiovascular disease]]<ref name="ESC">{{cite journal | vauthors=Graham I, Atar D, Borch-Johnsen K, Boysen G, Burell G, Cifkova R, Dallongeville J, De Backer G, Ebrahim S, Gjelsvik B, Herrmann-Lingen C, Hoes A, Humphries S, Knapton M, Perk J, Priori SG, Pyorala K, Reiner Z, Ruilope L, Sans-Menendez S, Scholte op Reimer W, Weissberg P, Wood D, Yarnell J, Zamorano JL, Walma E, Fitzgerald T, Cooney MT, Dudina A | title=European guidelines on cardiovascular disease prevention in clinical practice: executive summary: Fourth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular disease Prevention in Clinical Practice (Constituted by representatives of nine societies and by invited experts) | journal=European Heart Journal | volume=28 | issue=19 | pages=2375–414 | date=October 2007 | pmid=17726041 | doi=10.1093/eurheartj/ehm316 | author30 = European Society of Cardiology (ESC) Committee for Practice Guidelines (CPG) | doi-access=free | hdl=2066/52036 | hdl-access=free}}</ref>
|-
| [[Trans fat]]
| None
| [[Obesity]], [[cardiovascular disease]]
|-
| [[Unsaturated fat]]
| [[Fat-soluble]] vitamin deficiency
| [[Obesity]], [[cardiovascular disease]]
|-
| colspan="3" style="background: #dd99cc; text-align: center;"| '''[[Micronutrient]]s'''
|-
| [[Vitamin A]]
| [[Xerophthalmia]], [[night blindness]], and low testosterone levels{{citation needed|date=January 2020}}
| [[Hypervitaminosis A]] (cirrhosis, hair loss)
|-
| [[Thiamin|Vitamin B<sub>1</sub>]]
| [[Beri-Beri]]
|
|-
| [[Riboflavin|Vitamin B<sub>2</sub>]]
| Skin and corneal [[lesion]]s, cracking of skin and corneal unclearation
|
|-
| [[Niacin (nutrient)|Niacin]]
| [[Pellagra]]
| [[Dyspepsia]], [[cardiac arrhythmia]]s, birth defects
|-
| [[Biotin]]
| [[Biotin deficiency]]
| Reproductive and [[Teratology|teratogenic]] effects
|-
|[[Folate]]
|[[Megaloblastic anemia|Anemia]]
|Masks B<sub>12</sub> deficiency, which can lead to permanent [[neurological]] damage
|-
| [[Vitamin B12|Vitamin B<sub>12</sub>]]
| [[Pernicious anemia]], nerve cell damage
|
|-
| [[Vitamin C]]
| [[Scurvy]]
| [[Diarrhea]] causing [[dehydration]]
|-
| [[Vitamin D]]
| [[Rickets]], [[osteomalacia]]
| [[Hypervitaminosis D]] (dehydration, vomiting, constipation)
|-
| [[Vitamin E]]
| Neurological disease
| [[Hypervitaminosis E]] (anticoagulant: excessive bleeding)
|-
| [[Vitamin K]]
| [[Hemorrhage]]
|
|-
| [[Omega-3 fatty acid|Omega-3 fats]]
| [[Cardiovascular disease]]
| Bleeding, hemorrhages, [[hemorrhagic stroke]], reduced glycemic control among diabetics
|-
| [[Omega-6 fatty acid|Omega-6 fats]]
| None
| [[Cardiovascular disease]], [[Cancer]]
|-
| [[Cholesterol]]
|
| [[Cardiovascular disease]]:<ref name=ESC /> [[atherosclerotic plaques]], [[heart attack]], [[stroke]]
|-
| colspan="3" style="background: #dd99cc; text-align: center;"| '''[[Macromineral]]s'''
|-
| [[Calcium]]
| [[Osteoporosis]], [[Tetany (medical sign)|tetany]], [[carpopedal spasm]], [[laryngospasm]], [[cardiac arrhythmia]]s
| [[Fatigue (physical)|Fatigue]], [[clinical depression|depression]], [[confusion]], [[nausea]], [[vomiting]], [[constipation]], [[pancreatitis]], [[polyuria|increased urination]], [[kidney stones]], [[anorexia (symptom)|anorexia]]{{citation needed|date=January 2020}}
|-
| [[Magnesium]]
| [[Hypertension]]
| Weakness, nausea, vomiting, impaired breathing, and [[hypotension]]
|-
| [[Potassium]]
| [[Hypokalemia]], [[cardiac arrhythmia]]s
| [[Hyperkalemia]], [[palpitation]]s
|-
| [[Sodium]]
| [[Hyponatremia]]
| [[Hypernatremia]], [[hypertension]]
|-
| colspan="3" style="background:#dd99cc; text-align: center;"| '''[[Trace mineral]]s'''
|-
| [[Iron]]
| [[Anemia]]
| [[Cirrhosis]], [[hereditary hemochromatosis]], [[heart disease]], [[cardiovascular disease]]
|-
| [[Iodine]]
| [[Goiter]], [[hypothyroidism]]
| [[Iodine#Toxicity|Iodine toxicity]] (goiter, hypothyroidism)
|}

== Other substances ==
=== Alcohol (ethanol) ===
Pure ethanol provides 7 calories per gram. For [[distilled spirit]]s, a standard serving in the United States is 1.5 fluid ounces, which at 40% ethanol (80 proof), would be 14 grams and 98 calories.<ref>{{Cite web | url=https://health.gov/dietaryguidelines/2015/guidelines/appendix-9/#footnote2 | title=Appendix 9. Alcohol | website=health.gov | access-date=2020-01-03 | archive-date=2020-02-01 | archive-url=https://web.archive.org/web/20200201134130/https://health.gov/dietaryguidelines/2015/guidelines/appendix-9/#footnote2 | url-status=live}}</ref> Wine and beer contain a similar range of ethanol for servings of 5 ounces and 12 ounces, respectively, but these beverages also contain non-ethanol calories. A 5-ounce serving of wine contains 100 to 130 calories. A 12-ounce serving of beer contains 95 to 200 calories.<ref>{{Cite web | url=http://deanofstudents.cua.edu/alcohol/alcohol-facts/nutrition.cfm | title=Alcohol and Nutrition: The Calorie and Carb Breakdown! | website=The Catholic University of America | access-date=2020-01-03 | archive-date=2019-10-01 | archive-url=https://web.archive.org/web/20191001114847/http://deanofstudents.cua.edu/alcohol/alcohol-facts/nutrition.cfm | url-status=live}}</ref> According to the U.S. Department of Agriculture, based on [[NHANES]] 2013–2014 surveys, women ages 20 and up consume on average 6.8 grams/day and men consume on average 15.5 grams/day.<ref>{{cite web | url=https://www.ars.usda.gov/ARSUserFiles/80400530/pdf/1314/Table_1_NIN_GEN_13.pdf | archive-url=https://web.archive.org/web/20170212091141/https://www.ars.usda.gov/ARSUserFiles/80400530/pdf/1314/Table_1_NIN_GEN_13.pdf | archive-date=2017-02-12 | url-status=live | title=What We Eat in America, NHANES 2013–2014}}</ref> Ignoring the non-alcohol contribution of those beverages, the average ethanol calorie contributions are 48 and 108 cal/day. Alcoholic beverages are considered [[empty calorie]] foods because other than calories, these contribute no essential nutrients.

=== Phytochemicals ===
{{Main|Phytochemical}}
{{See also|List of antioxidants in food}}

Phytochemicals such as [[polyphenol]]s are compounds produced naturally in plants (phyto means "plant" in Greek). In general, the term identifies compounds that are prevalent in plant foods, but are not proven to be essential for human nutrition, as of 2018. There is no conclusive evidence in humans that polyphenols or other non-nutrient compounds from plants confer health benefits, mainly because these compounds have poor [[bioavailability]], i.e., following ingestion, they are digested into smaller [[metabolite]]s with unknown functions, then are rapidly eliminated from the body.<ref>{{cite journal | pmc=2871118 | year=2010 | last1=d'Archivio | first1=M. | title=Bioavailability of the polyphenols: status and controversies | journal=International Journal of Molecular Sciences | volume=11 | issue=4 | pages=1321–42 | last2=Filesi | first2=C. | last3=Varì | first3=R. | last4=Scazzocchio | first4=B. | last5=Masella | first5=R. | pmid=20480022 | doi=10.3390/ijms11041321 | doi-access=free}}</ref><ref name="acs">{{cite web | url=https://www.cancer.org/healthy/eat-healthy-get-active/acs-guidelines-nutrition-physical-activity-cancer-prevention/common-questions.html?_ga=2.57358826.1597423548.1542983382-1390869997.1542983382 | title=Common questions about diet and cancer | date=5 February 2016 | publisher=[[American Cancer Society]] | access-date=23 November 2018 | archive-date=23 November 2018 | archive-url=https://web.archive.org/web/20181123201755/https://www.cancer.org/healthy/eat-healthy-get-active/acs-guidelines-nutrition-physical-activity-cancer-prevention/common-questions.html?_ga=2.57358826.1597423548.1542983382-1390869997.1542983382 | url-status=live}}</ref>

[[File:Colorfull.jpg|thumb|Colorful fruits and vegetables may be components of a healthy diet.]]

== Intestinal microbiome ==
{{Main|Gut flora}}
The intestines contain a large population of [[gut flora]]. In humans, the four dominant [[phylum|phyla]] are [[Bacillota]], [[Bacteroidota]], [[Actinomycetota]], and [[Pseudomonadota]].<ref name="pmid24388028">{{cite journal | vauthors=Khanna S, Tosh PK | title=A clinician's primer on the role of the microbiome in human health and disease | journal=Mayo Clin. Proc. | volume=89 | issue=1 | pages=107–14 | date=January 2014 | pmid=24388028 | doi=10.1016/j.mayocp.2013.10.011 | doi-access=free}}</ref> They are essential to [[digestion]] and are also affected by food that is consumed. Bacteria are essential for metabolizing food substrates and thereby increasing energy output, and produce a great variety of metabolites, including vitamins and [[short-chain fatty acids]] that contribute to the metabolism in a wide variety of ways.<ref>{{cite journal | last1=Kolmeder | first1=Carolin A. | last2=de Vos | first2=Willem M. | title=Roadmap to functional characterization of the human intestinal microbiota in its interaction with the host | journal=Journal of Pharmaceutical and Biomedical Analysis | date=29 October 2020 | volume=194 | page=113751 | doi=10.1016/j.jpba.2020.113751 | pmid=33328144 | s2cid=229300476 | doi-access=free}}</ref> These metabolites are responsible for stimulating cell growth, repressing the growth of harmful bacteria, priming the immune system to respond only to pathogens, helping to maintain a healthy gut barrier, control gene expression by epigenetic regulation<ref>{{cite journal | last1=Gu | first1=Bon-Hee | last2=Kim | first2=Myunghoo | last3=Yun | first3=Cheol-Heui | title=Regulation of gastrointestinal immunity by metabolites | journal=Nutrients | date=7 January 2021 | volume=13 | issue=1 | page=167 | doi=10.3390/nu13010167 | pmid=33430497 | pmc=7826526 | doi-access=free}}</ref> and defending against some infectious diseases.<ref name="Guarner and Malagelada 2003b">{{cite journal | doi=10.1016/S0140-6736(03)12489-0 | title=Gut flora in health and disease | year=2003 | last1=Guarner | first1=F | last2=Malagelada | first2=J | journal=The Lancet | volume=361 | issue=9356 | pages=512–19 | pmid=12583961 | s2cid=38767655}}</ref>

== Global nutrition challenges ==
{{Duplication|section=yes|dupe=malnutrition|date=February 2021}}
The challenges facing global nutrition are disease, child malnutrition, obesity, and vitamin deficiency.{{medical citation needed|date=July 2015}}

=== Disease ===
The most common non-infectious diseases worldwide, that contribute most to the global mortality rate, are cardiovascular diseases, various cancers, diabetes, and chronic respiratory problems, all of which are linked to poor nutrition. Nutrition and diet are closely associated with the leading causes of death, including cardiovascular disease and cancer. Obesity and high sodium intake can contribute to ischemic heart disease, while consumption of fruits and vegetables [[nutrition and cancer|can decrease the risk]] of developing cancer.<ref name="GNP" />

Food-borne and infectious diseases can result in malnutrition, and malnutrition exacerbates infectious disease. Poor nutrition leaves children and adults more susceptible to contracting life-threatening diseases such as diarrheal infections and respiratory infections.<ref name="Progress for Children" /> According to the WHO, in 2011, 6.9 million children died of infectious diseases like pneumonia, diarrhea, malaria, and neonatal conditions, of which at least one third were associated with undernutrition.<ref>{{cite news | title=UNICEF 2012 Progress Report: Rapid progress in child survival | url=https://www.who.int/pmnch/media/news/2012/20120913_unicef_childsurvivalreport/en/ | access-date=28 May 2016 | publisher=World Health Organization | date=18 September 2012 | archive-date=17 June 2016 | archive-url=https://web.archive.org/web/20160617071432/http://www.who.int/pmnch/media/news/2012/20120913_unicef_childsurvivalreport/en/ | url-status=live}}</ref><ref name="ENA4">WHO. World health statistics 2013: a wealth of information on global public health. Geneva, WHO, 2013. pp. 5-7</ref><ref name="ENA6">{{cite journal | vauthors=Liu L, Johnson HL, Cousens S, Perin J, Scott S, Lawn JE, Rudan I, Campbell H, Cibulskis R, Li M, Mathers C, Black RE | title=Global, regional, and national causes of child mortality: an updated systematic analysis for 2010 with time trends since 2000 | journal=Lancet | volume=379 | issue=9832 | pages=2151–61 | date=June 2012 | pmid=22579125 | doi=10.1016/S0140-6736(12)60560-1 | author13=Child Health Epidemiology Reference Group of WHO UNICEF | s2cid=43866899}}</ref>

=== Child malnutrition ===
{{Main|Undernutrition in children|Childhood obesity}}
According to UNICEF, in 2011, 101 million children across the globe were underweight and one in four children, 165 million, were stunted in growth.<ref name="ENA1">UNICEF, WHO, World Bank. UNICEF-WHO-World Bank Joint child malnutrition estimates. New York, Geneva & Washington DC, UNICEF, WHO & World Bank, 2012 ([https://web.archive.org/web/20110605204517/http://www.who.int/nutgrowthdb/estimates/en/index.html], accessed 27 March 2013)</ref> Simultaneously, there are 43 million children under five who are overweight or obese.<ref name="Essential Nutrition Actions" /> Nearly 20 million children under five suffer from severe acute malnutrition, a life-threatening condition requiring urgent treatment.<ref name="Essential Nutrition Actions" /> According to estimations at [[UNICEF]], [[hunger]] will be responsible for 5.6 million deaths of children under the age of five this year.<ref name="Progress for Children" /> These all represent significant public health emergencies.<ref name="GNP">WHO (2013). Global Nutrition Policy. Report of a WHO Expert Committee. Geneva, World Health Organization. http://apps.who.int/iris/bitstream/10665/84408/1/9789241505529_eng.pdf {{Webarchive|url=https://web.archive.org/web/20131225054022/http://apps.who.int/iris/bitstream/10665/84408/1/9789241505529_eng.pdf |date=2013-12-25 }}</ref> This is because proper maternal and child nutrition has immense consequences for survival, acute and chronic disease incidence, normal growth, and economic productivity of individuals.<ref name="Maternal undernutrition">{{cite journal | vauthors=Black RE, Victora CG, Walker SP, Bhutta ZA, Christian P, de Onis M, Ezzati M, Grantham-McGregor S, Katz J, Martorell R, Uauy R | title=Maternal and child undernutrition and overweight in low-income and middle-income countries | journal=Lancet | volume=382 | issue=9890 | pages=427–451 | date=August 2013 | pmid=23746772 | doi=10.1016/S0140-6736(13)60937-X | author12=Maternal Child Nutrition Study Group | s2cid=12237910}}</ref>

Childhood [[malnutrition]] is common and contributes to the [[Disease burden|global burden of disease]].<ref>{{cite journal | vauthors=Murray CJ, Lopez AD | title=Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study | journal=Lancet | volume=349 | issue=9063 | pages=1436–42 | date=May 1997 | pmid=9164317 | doi=10.1016/S0140-6736(96)07495-8 | s2cid=2569153}}</ref> Childhood is a particularly important time to achieve good nutrition status, because poor nutrition has the capability to lock a child in a vicious cycle of disease susceptibility and recurring sickness, which threatens cognitive and social development.<ref name="Progress for Children" /> Undernutrition and bias in access to food and health services leaves children less likely to attend or perform well in school.<ref name="Progress for Children" />

=== Undernutrition ===
{{Main|Undernutrition}}
[[UNICEF]] defines undernutrition "as the outcome of insufficient food intake (hunger) and repeated infectious diseases. Undernutrition includes being underweight for one's age, too short for one's age ([[stunted growth]]), dangerously thin ([[muscle wasting]]), and deficient in vitamins and minerals ([[micronutrient malnutrition]]).<ref name="Progress for Children" /> Under nutrition causes 53% of deaths of children under five across the world.<ref name="Progress for Children" /> It has been estimated that undernutrition is the underlying cause for 35% of child deaths.<ref name="Black">{{cite journal | vauthors=Black RE, Allen LH, Bhutta ZA, Caulfield LE, de Onis M, Ezzati M, Mathers C, Rivera J | title=Maternal and child undernutrition: global and regional exposures and health consequences | journal=Lancet | volume=371 | issue=9608 | pages=243–60 | date=January 2008 | pmid=18207566 | doi=10.1016/s0140-6736(07)61690-0 | s2cid=3910132}}</ref> The Maternal and Child Nutrition Study Group estimate that under nutrition, "including fetal growth restriction, stunting, wasting, deficiencies of vitamin A and zinc along with suboptimum breastfeeding—is a cause of 3.1 million child deaths and infant mortality, or 45% of all child deaths in 2011".<ref name="Maternal undernutrition" />

When humans are undernourished, they no longer maintain normal bodily functions, such as growth, resistance to infection, or have insufficient drive for every everyday tasks and unsatisfactory performance in school or work.<ref name="Progress for Children" /> Major causes of under nutrition in young children include lack of proper breast feeding for infants and illnesses such as [[diarrhea]], [[pneumonia]], [[malaria]], and [[HIV/AIDS]].<ref name="Progress for Children" /> According to UNICEF 146 million children across the globe, that one out of four under the age of five, are underweight.<ref name="Progress for Children" /> The number of underweight children has decreased since 1990, from 33 percent to 28 percent between 1990 and 2004.<ref name="Progress for Children" /> Underweight and stunted children are more susceptible to infection, more likely to fall behind in academics and develop non-infectious diseases, ultimately affecting their livelihood.<ref name="IMPROVING CHILD NUTRITION">{{cite book | author=UNICEF | date=April 15, 2013 <!-- For this date, see https://reliefweb.int/report/world/improving-child-nutrition-achievable-imperative-global-progress --> | title=Improving child nutrition: The achievable imperative for global progress | publication-place=New York City | publisher=Author | isbn=978-92-806-4686-3 | oclc=847679768 | url=https://data.unicef.org/wp-content/uploads/2015/12/NutritionReport_April2013_Final_29.pdf <!-- https://reliefweb.int/attachments/22378890-3058-3ffe-8241-5c156bb89f9b/Improving%20child%20nutrition%20The%20achievable%20imperative%20for%20global%20progress.pdf https://web.archive.org/web/20130928231307/http://www.unicef.org/publications/files/Nutrition_Report_final_lo_res_8_April.pdf --> }}<!-- Also available in other languages at https://web.archive.org/web/20130513170829/http://www.unicef.org/publications/index_68661.html --></ref> Therefore, undernutrition can result in an accumulation of afflictions and health deficiencies which results in less productivity individually and as a community.<ref name="Progress for Children" />

Many children are born with the inherent disadvantage of [[low birth weight]], often caused by [[intrauterine]] growth restriction and poor maternal nutrition, which results in affected growth, development and health throughout the course of their lifetime.<ref name="GNP" /> Children born at low birth weight (less than 5.5 pounds or 2.5&nbsp;kg), are less likely to be healthy and are more susceptible to disease and early death.<ref name="Progress for Children" /> Those born at low birth weight also are likely to have a depressed immune system, which can increase their chances of [[heart disease]] and [[diabetes]] later on in life.<ref name="Progress for Children" /> Because 96% of low birth weight occurs in the developing world, low birth weight has been associated with childbirth in impoverished areas where the birth mother typically exhibits poor nutritional status under harsh and demanding living conditions.<ref name="Progress for Children" />

Stunting and other forms of undernutrition reduces a child's chance of survival and hinders their optimal growth and health.<ref name="IMPROVING CHILD NUTRITION" /> Stunting has demonstrated association with poor brain development, which reduces [[cognitive ability]], academic performance and future earning potential.<ref name="IMPROVING CHILD NUTRITION" /> Important determinants of stunting include the quality and frequency of infant and child feeding, infectious disease susceptibility, and the mother's nutrition and health status.<ref name="IMPROVING CHILD NUTRITION" /> Undernourished mothers are more likely to birth stunted children, perpetuating a cycle of undernutrition and poverty.<ref name="IMPROVING CHILD NUTRITION" /> Stunted children are more likely to develop obesity and chronic diseases upon reaching adulthood.<ref name="IMPROVING CHILD NUTRITION" /> Therefore, malnutrition resulting in stunting can further worsen the obesity epidemic, especially in low and middle income countries.<ref name="IMPROVING CHILD NUTRITION" /> This creates even new economic and social challenges for vulnerable impoverished groups.<ref name="IMPROVING CHILD NUTRITION" />

Data on global and regional food supply shows that consumption rose from 2011 to 2012 in all regions. Diets became more diverse, with a decrease in consumption of cereals and roots and an increase in fruits, vegetables, and meat products.<ref name="FAO2012">FAO (2012). The state of food insecurity in the world 2012: Economic growth is necessary but not sufficient to accelerate reduction of hunger and malnutrition. Rome, Food and Agricultural Organization of the United Nations. http://www.fao.org/publications/sofi/en/ {{Webarchive|url=https://web.archive.org/web/20210214205751/http://www.fao.org/publications/sofi/en/ |date=2021-02-14 }} (Accessed 7 December 2012.).</ref> However, this increase masks the discrepancies between nations, where Africa, in particular, saw a decrease in food consumption over the same years.<ref name="FAO2012" /> This information is derived from food balance sheets that reflect national food supplies, however, this does not necessarily reflect the distribution of [[micronutrient]]s and [[macronutrients]].<ref name="FAO2012" /> Often inequality in food access leaves distribution which uneven, resulting in undernourishment for some and obesity for others.<ref name="FAO2012" />

Undernourishment, or hunger, according to the [[Food and Agriculture Organization]] (FAO), is dietary intake below the minimum daily energy requirement.<ref name="FAO" /> The amount of undernourishment is calculated utilizing the average amount of food available for consumption, the size of the population, the relative disparities in access to the food, and the minimum calories required for each individual.<ref name="FAO" /> According to [[FAO]], 868 million people (12% of the global population) were undernourished in 2012.<ref name="FAO" /> This has decreased across the world since 1990, in all regions except for Africa, where undernourishment has steadily increased.<ref name="FAO" /> However, the rates of decrease are not sufficient to meet the first [[Millennium Development Goals|Millennium Development Goal]] of halving hunger between 1990 and 2015.<ref name="FAO" /> The global financial, economic, and food price crisis in 2008 drove many people to hunger, especially women and children. The spike in [[food prices]] prevented many people from escaping poverty, because the poor spend a larger proportion of their income on food and farmers are net consumers of food.<ref name="UNSCN09">UNSCN (2009). Global financial and economic crisis – The most vulnerable are at increased risk of hunger and malnutrition. United Nations Standing Committee on Nutrition. http://www.unscn.org/en/publications/nutrition_briefs/#Nutrition_impacts_of_global_food_and_financial_crises {{Webarchive|url=https://web.archive.org/web/20131203063523/http://www.unscn.org/en/publications/nutrition_briefs/#Nutrition_impacts_of_global_food_and_financial_crises |date=3 December 2013 }}.</ref> High food prices cause consumers to have less purchasing power and to substitute more-nutritious foods with low-cost alternatives.<ref name="IBRD">IBRD, World Bank (2012). Global Monitoring Report 2012: Food prices, nutrition, and the Millennium Development Goals. International Bank for Reconstruction and Development (IBRD)/World Bank, Washington, DC.</ref>

=== Adult overweight and obesity ===
{{Main|Overnutrition|Obesity|Overweight}}
Malnutrition in [[Industrialized countries|Industrialized nations]] is primarily due to non-nutritious carbohydrates sources resulting in excess caloric intake, which has contributed to the obesity epidemic affecting both developed and certain developing nations.<ref name=P4C48>{{cite journal | vauthors=Darnton-Hill I, Nishida C, James WP | year=2004 | title=A life course approach to diet, nutrition and the prevention of chronic diseases | journal=Public Health Nutrition | volume=7 | issue=1A | pages=101–121 | doi=10.1079/phn2003584 | pmid=14972056 | doi-access=free}}</ref> In 2008, 35% of adults above the age of 20 years were overweight (BMI ≥ 25&nbsp;kg/m<sup>2</sup>), a prevalence that has doubled worldwide between 1980 and 2008.<ref name="ENA25">{{cite journal | vauthors=Finucane MM, Stevens GA, Cowan MJ, Danaei G, Lin JK, Paciorek CJ, Singh GM, Gutierrez HR, Lu Y, Bahalim AN, Farzadfar F, Riley LM, Ezzati M | title=National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9·1 million participants | journal=Lancet | volume=377 | issue=9765 | pages=557–67 | date=February 2011 | pmid=21295846 | pmc=4472365 | doi=10.1016/S0140-6736(10)62037-5 | author14=Global Burden of Metabolic Risk Factors of Chronic Diseases Collaborating Group (Body Mass Index)}}</ref> Also 10% of men and 14% of women were obese, with a [[body mass index]] (BMI) greater than 30.<ref name="WHOglobe" /> Rates of overweight and obesity vary across the globe, with the highest prevalence in the Americas, followed by European nations, where over 50% of the population is overweight or obese.<ref name="WHOglobe" />

Obesity is more prevalent among upper-middle to high income groups compared to lower income divisions.<ref name="WHOglobe" /> Women are more likely than men to be obese, where the rate of obesity in women doubled from 8% to 14% between 1980 and 2008.<ref name="WHOglobe" /> Being overweight as a child has become an increasingly important statistic as an indicator for later development of obesity and non-infectious diseases such as [[cardiovascular disease]].<ref name="Maternal undernutrition" /> In several western European nations, the prevalence of overweight and obese children rose by 10% from 1980 to 1990, a rate that has begun to accelerate recently.<ref name="Progress for Children" />

=== Vitamin and mineral malnutrition ===
Vitamins and minerals are essential to the proper functioning and maintenance of the human body.<ref name="stein-2010">{{Cite journal | title=Global Impacts of Human Mineral Malnutrition | last=Stein | first=A. J. | date=2010 | journal=Plant and Soil | doi=10.1007/s11104-009-0228-2 | volume=335 | issue=1/2 | pages=133–154 | bibcode=2010PlSoi.335..133S | s2cid=23959785}}</ref> There are 20 trace elements and minerals that are essential in small quantities to body function and overall human health.<ref name="stein-2010" />

[[Iron deficiency]] is the most common inadequate nutrient worldwide, affecting approximately 2 billion people.<ref name="ENA12">WHO. Iron deficiency anemia: assessment, prevention, and control. A guide for program managers. Geneva, WHO, 2001{{page needed|date=November 2013}}</ref> Globally, anemia affects 1.6 billion people, and represents a public health emergency in mothers and children under five.<ref name="Iron">WHO (2001). Iron deficiency anemia: Assessment, prevention, and control. A guide for program managers. Geneva, World Health Organization.</ref> The World Health Organization estimates that there exists 469 million women of reproductive age and approximately 600 million preschool and school-age children worldwide who are anemic.<ref name="ENA13">WHO, Centers for Disease Control. Worldwide prevalence of anemia 1993–2005: WHO global database of anemia. Geneva, WHO, 2008.{{page needed|date=November 2013}}</ref> [[Anemia]], especially iron-deficient anemia, is a critical problem for cognitive developments in children, and its presence leads to maternal deaths and poor brain and motor development in children.<ref name="Progress for Children" /> The development of [https://www.mayoclinic.org/diseases-conditions/anemia/symptoms-causes/syc-20351360#:~:text=Overview,weakness%20and%20shortness%20of%20breath. anemia] affects mothers and children more because infants and children have higher iron requirements for growth.<ref name="ENA14">W Institute of Medicine. Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Washington DC, National Academy Press, 2001{{page needed|date=November 2013}}</ref> Health consequences for iron deficiency in young children include increased perinatal mortality, delayed mental and physical development, negative behavioral consequences, reduced auditory and visual function, and impaired physical performance.<ref name="ENA16">{{cite journal | vauthors=Algarín C, Peirano P, Garrido M, Pizarro F, Lozoff B | title=Iron deficiency anemia in infancy: long-lasting effects on auditory and visual system functioning | journal=Pediatric Research | volume=53 | issue=2 | pages=217–23 | date=February 2003 | pmid=12538778 | doi=10.1203/01.PDR.0000047657.23156.55 | doi-access=free}}</ref> The harm caused by iron deficiency during child development cannot be reversed and result in reduced academic performance, poor physical work capacity, and decreased productivity in adulthood.<ref name="Essential Nutrition Actions" /> Mothers are also very susceptible to iron-deficient anemia because women lose iron during menstruation, and rarely supplement it in their diet.<ref name="Essential Nutrition Actions" /> Maternal iron deficiency anemia increases the chances of maternal mortality, contributing to at least 18% of maternal deaths in low and middle income countries.<ref name="ENA20">"Global health risks – Mortality and burden of disease attributable to selected major risks". Geneva, WHO, 2009 (http://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_report_full.pdf {{Webarchive|url=https://web.archive.org/web/20130810075230/http://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_report_full.pdf |date=2013-08-10 }} accessed 31 July 2017).{{page needed|date=November 2013}}</ref>

[[Vitamin A]] plays an essential role in developing the immune system in children, therefore, it is considered an essential micronutrient that can greatly affect health.<ref name="Progress for Children" /> However, because of the expense of testing for deficiencies, many developing nations have not been able to fully detect and address vitamin A deficiency, leaving vitamin A deficiency considered a silent hunger.<ref name="Progress for Children" /> According to estimates, subclinical vitamin A deficiency, characterized by low retinol levels, affects 190 million pre-school children and 19 million mothers worldwide.<ref name="VitAWHO">WHO (2009). Global prevalence of vitamin A deficiency in populations at risk 1995–2005. WHO Global Database on Vitamin A Deficiency. Geneva, World Health Organization. {{cite web | url=http://www.edu-lib.us/whqlibdoc.who.int/publications/2009/9789241598019_eng.pdf | title=Archived copy | access-date=1 March 2014 | url-status=usurped | archive-url=https://web.archive.org/web/20150923233815/http://www.edu-lib.us/whqlibdoc.who.int/publications/2009/9789241598019_eng.pdf | archive-date=23 September 2015}}</ref>

The WHO estimates that 5.2 million of these children under five are affected by night blindness, which is considered clinical vitamin A deficiency.<ref name="ENA9">WHO. Global prevalence of vitamin A deficiency in populations at risk 1995–2005: WHO Global database of vitamin A deficiency. Geneva, WHO, 2009.</ref> Severe vitamin A deficiency (VAD) for developing children can result in visual impairments, anemia and weakened immunity, and increase their risk of morbidity and mortality from infectious disease.<ref name="ENA10">Sommer A, West KP Jr. Vitamin A deficiency: health, survival, and vision. New York, Oxford University Press, 1996 p. 19 {{ISBN|0195088247}}</ref> This also presents a problem for women, with WHO estimating that 9.8 million women are affected by night blindness.<ref name="ENA11">{{cite journal | vauthors=Lozoff B, Jimenez E, Wolf AW | title=Long-term developmental outcome of infants with iron deficiency | journal=The New England Journal of Medicine | volume=325 | issue=10 | pages=687–94 | date=September 1991 | pmid=1870641 | doi=10.1056/NEJM199109053251004 | doi-access=free}}</ref> Clinical vitamin A deficiency is particularly common among pregnant women, with prevalence rates as high as 9.8% in South-East Asia.<ref name="VitAWHO" />

Estimates say that 28.5% of the global population is iodine deficient, representing 1.88 billion individuals.<ref name="Iodine">{{cite journal | vauthors=Andersson M, Karumbunathan V, Zimmermann MB | title=Global iodine status in 2011 and trends over the past decade | journal=The Journal of Nutrition | volume=142 | issue=4 | pages=744–50 | date=April 2012 | pmid=22378324 | doi=10.3945/jn.111.149393 | doi-access=free}}</ref> Although salt iodization programs have reduced the prevalence of iodine deficiency, this is still a public health concern in 32 nations. Moderate deficiencies are common in Europe and Africa, and over consumption is common in the Americas.<ref name="GNP" /> Iodine-deficient diets can interfere with adequate thyroid hormone production, which is responsible for normal growth in the brain and nervous system. This ultimately leads to poor school performance and impaired intellectual capabilities.<ref name="Progress for Children" />

=== Infant and young child feeding ===
Improvement of breast feeding practices, like early initiation and exclusive breast feeding for the first two years of life, could save the lives of 1.5 million children annually.<ref name=ENA7>{{cite journal | vauthors=Jones G, Steketee RW, Black RE, Bhutta ZA, Morris SS | title=How many child deaths can we prevent this year? | journal=Lancet | volume=362 | issue=9377 | pages=65–71 | date=July 2003 | pmid=12853204 | doi=10.1016/S0140-6736(03)13811-1 | author6=Bellagio Child Survival Study Group | s2cid=17908665}}</ref> Nutrition interventions targeted at infants aged 0–5 months first encourages early initiation of breastfeeding.<ref name="Essential Nutrition Actions" /> Though the relationship between early initiation of breast feeding and improved health outcomes has not been formally established, a recent study in [[Ghana]] suggests a causal relationship between early initiation and reduced infection-caused neo-natal deaths.<ref name="Essential Nutrition Actions" /> Also, experts promote exclusive breastfeeding, rather than using formula, which has shown to promote optimal growth, development, and health of infants.<ref name=ENA2P7>WHO. Report of the expert consultation on the optimal duration of exclusive breastfeeding. Geneva, WHO, 2001.{{page needed|date=November 2013}}</ref> Exclusive breastfeeding often indicates nutritional status because infants that consume breast milk are more likely to receive all adequate nourishment and nutrients that will aid their developing body and immune system. This leaves children less likely to contract diarrheal diseases and respiratory infections.<ref name="Progress for Children" />

Besides the quality and frequency of breastfeeding, the nutritional status of mothers affects infant health. When mothers do not receive proper nutrition, it threatens the wellness and potential of their children.<ref name="Progress for Children" /> Well-nourished women are less likely to experience risks of birth and are more likely to deliver children who will develop well physically and mentally.<ref name="Progress for Children" /> Maternal undernutrition increases the chances of low-birth weight, which can increase the risk of infections and asphyxia in fetuses, increasing the probability of neonatal deaths.<ref name=ENA23>{{cite journal | vauthors=Ramakrishnan U, Yip R | title=Experiences and challenges in industrialized countries: control of iron deficiency in industrialized countries | journal=The Journal of Nutrition | volume=132 | issue=4 Suppl | pages=820S–4S | date=April 2002 | pmid=11925488 | doi=10.1093/jn/132.4.820S | doi-access=free}}</ref> Growth failure during intrauterine conditions, associated with improper mother nutrition, can contribute to lifelong health complications.<ref name="Essential Nutrition Actions" /> Approximately 13 million children are born with [[intrauterine growth restriction]] annually.<ref name=ENA2>{{cite journal | vauthors=Black RE, Allen LH, Bhutta ZA, Caulfield LE, de Onis M, Ezzati M, Mathers C, Rivera J | title=Maternal and child undernutrition: global and regional exposures and health consequences | journal=Lancet | volume=371 | issue=9608 | pages=243–60 | date=January 2008 | pmid=18207566 | doi=10.1016/S0140-6736(07)61690-0 | s2cid=3910132}}</ref>

=== Anorexia nervosa ===
[[Anorexia nervosa]] stands out as the [[psychiatric disorder]] with the highest mortality rate. It affects approximately 0.3% of young women and is especially common among teenage girls, with the average onset at around 15 years old. The disorder predominantly impacts females, with 80-90% of those diagnosed being women. Anorexia is the leading cause of significant weight loss in young women and is the primary reason for their admission to child and adolescent hospital services.<ref name="morris-2007">{{Cite journal | last1=Morris | first1=Jane | last2=Twaddle | first2=Sara | date=2007-04-28 | title=Anorexia nervosa | journal=BMJ | language=en | volume=334 | issue=7599 | pages=894–898 | doi=10.1136/bmj.39171.616840.BE | issn=0959-8138 | pmc=1857759 | pmid=17463461}}</ref> In most cases, a clear diagnosis of weight loss driven by psychological factors can be made without resorting to a series of complex tests. Basic medical evaluations, including blood tests, [[Electrocardiography|electrocardiograms]], and tracking the patient's weight and measurements, not only help in identifying underlying issues but also provide a reason for the patient to return for follow-up discussions. These follow-ups can often reveal psychological challenges. When weight loss is hidden, symptoms such as depression, obsessive behaviors, infertility, or [[amenorrhea]] may be the first signs that there is cause for concern.<ref name="morris-2007" /> Although relatively uncommon, eating disorders can negatively affect menstruation, fertility, and maternal and fetal well-being. Among infertile women with amenorrhea or [[oligomenorrhea]] due to eating disorders, 58% had menstrual irregularities, according to preliminary research in 1990.<ref>{{cite journal | last1=Stewart | first1=D. E. | last2=Robinson | first2=E. | last3=Goldbloom | first3=D. S. | last4=Wright | first4=C. | date=1990 | title=Infertility and eating disorders | journal=American Journal of Obstetrics and Gynecology | volume=163 | issue=4 | pages=1196–1199 | doi=10.1016/0002-9378(90)90688-4 | issn=0002-9378 | pmid=2220927}}</ref> Recent research has shown no significant difference in fertility between women with a history of anorexia nervosa and those without, suggesting that despite experiencing high rates of menstrual irregularities, women with anorexia nervosa are still achieving pregnancy.<ref>{{Cite journal | last1=Hoffman | first1=Elizabeth R | last2=Zerwas | first2=Stephanie C | last3=Bulik | first3=Cynthia M | date=July 2011 | title=Reproductive issues in anorexia nervosa | journal=Expert Review of Obstetrics & Gynecology | language=en | volume=6 | issue=4 | pages=403–414 | doi=10.1586/eog.11.31 | issn=1747-4108 | pmc=3192363 | pmid=22003362}}</ref>

=== Nutrition literacy ===
The findings of the 2003 National Assessment of Adult Literacy (NAAL), conducted by the US Department of Education, provide a basis upon which to frame the nutrition literacy problem in the U.S. NAAL introduced the first-ever measure of "the degree to which individuals have the capacity to obtain, process and understand basic health information and services needed to make appropriate health decisions"&nbsp;– an objective of Healthy People 2010<ref>Baldi, S. (ED.) et al. (2009). [http://nces.ed.gov/pubsearch/pubsinfo.asp?pubid=2009476 Technical Report and Data File User's Manual for the 2003 National Assessment of Adult Literacy (NCES 2009–2047)] {{Webarchive|url=https://web.archive.org/web/20220527011548/https://nces.ed.gov/pubsearch/pubsinfo.asp?pubid=2009476 |date=2022-05-27 }}. U.S. Department of Education, National Center for Education Statistics. Washington, DC: U.S. Government Printing Office.</ref> and of which nutrition literacy might be considered an important subset. On a scale of below basic, basic, intermediate and proficient, NAAL found 13 percent of adult Americans have proficient health literacy, 44% have intermediate literacy, 29 percent have basic literacy and 14 percent have below basic health literacy. The study found that health literacy increases with education and people living below the level of poverty have lower health literacy than those above it.

Another study examining the health and nutrition literacy status of residents of the lower [[Mississippi Delta]] found that 52 percent of participants had a high likelihood of limited literacy skills.<ref name="cdc.gov">{{cite journal | vauthors=Zoellner J, Connell C, Bounds W, Crook L, Yadrick K | year=2009 | title=Nutrition Literacy Status and Preferred Nutrition Communications Channels Among Adults in the Lower Mississippi Delta | journal=Preventing Chronic Disease | volume=6 | issue=4 | pages=A128 | url=https://www.cdc.gov/pcd/issues/2009/oct/08_0016.htm | pmid=19755004 | pmc=2774642 | access-date=2020-01-03 | archive-date=2022-08-07 | archive-url=https://web.archive.org/web/20220807213022/https://www.cdc.gov/pcd/issues/2009/oct/08_0016.htm | url-status=live}}</ref> While a precise comparison between the NAAL and Delta studies is difficult, primarily because of [[methodological]] differences, Zoellner et al. suggest that health literacy rates in the Mississippi Delta region are different from the U.S. general population and that they help establish the scope of the problem of health literacy among adults in the Delta region. For example, only 12 percent of study participants identified the [[MyPyramid]] graphic two years after it had been launched by the [[United States Department of Agriculture]] (USDA). The study also found significant relationships between nutrition literacy and income level and nutrition literacy and educational attainment<ref name="cdc.gov" /> further delineating priorities for the region.

These statistics point to the complexities surrounding the lack of health/nutrition literacy and reveal the degree to which they are embedded in the social structure and interconnected with other problems. Among these problems are the lack of information about food choices, a lack of understanding of nutritional information and its application to individual circumstances, limited or difficult access to healthful foods, and a range of cultural influences and [[Socioeconomic status|socioeconomic]] constraints such as low levels of education and high levels of poverty that decrease opportunities for healthful eating and living.

The links between low health literacy and poor health outcomes has been widely documented<ref>Berkman N.D., Sheridan, S.L., Donahue, K.E., Halpern, D.J., Viera, A., Crotty, K., Viswanathan, M. (2011). [https://www.ncbi.nlm.nih.gov/books/NBK82434/ Health and Literacy Intervention Outcomes: an Updated Systematic Review. Evidence Report/Technology Assessment no. 199] {{Webarchive|url=https://web.archive.org/web/20220401064005/https://www.ncbi.nlm.nih.gov/books/NBK82434/ |date=2022-04-01 }}. Prepared by RTI International – University of North Carolina Evidence-based Practice Center. Publication Number 11-E006. Rockville, MD. Agency for Healthcare Research and Quality.</ref> and there is evidence that some interventions to improve health literacy have produced successful results in the primary care setting. More must be done to further our understanding of nutrition literacy specific interventions in non-primary care settings<ref name="cdc.gov" /> in order to achieve better health outcomes.

== International food insecurity and malnutrition ==
{{further|Underweight|Food security|Epidemiology of malnutrition}}
According to UNICEF, South Asia has the highest levels of underweight children under five, followed by sub-Saharan Africans nations, with Industrialized countries and Latin nations having the lowest rates.<ref name="Progress for Children" />

=== Industrialized countries ===
According to [[UNICEF]], the [[Commonwealth of Independent States]] has the lowest rates of [[stunted growth|stunting]] and [[wasting]], at 14 percent and 3 percent.<ref name="Progress for Children" /> The nations of Estonia, Finland, Iceland, Lithuania and Sweden have the lowest prevalence of low [[birthweight]] children in the world- at 4%.<ref name="Progress for Children" /> Proper prenatal nutrition is responsible for this small prevalence of low birthweight infants.<ref name="Progress for Children" /> However, low birthweight rates are increasing, due to the use of [[fertility drugs]], resulting in multiple births, women bearing children at an older age, and the advancement of technology allowing more pre-term infants to survive.<ref name="Progress for Children" /> Industrialized nations more often face malnutrition in the form of over-nutrition from excess calories and non-nutritious carbohydrates, which has contributed greatly to the public health epidemic of obesity.<ref name="P4C48" /> Disparities, according to gender, geographic location and socio-economic position, both within and between countries, represent the biggest threat to child nutrition in industrialized countries. These disparities are a direct product of social inequalities and [[social inequalities]] are rising throughout the industrialized world, particularly in Europe.<ref name="Progress for Children" />

=== North America ===

==== United States ====
In the United States, 2% of children are underweight, with under 1% [[stunted growth|stunted]] and 6% are [[wasting]].<ref name="Progress for Children" />
[[File:New York National Guard Assisting Volunteers.jpg|thumb|New York National Guard Assisting Volunteers packing turkeys for families facing food insecurity]]
[[Dietitian]]s are registered (RD) or licensed (LD) with the Commission for Dietetic Registration and the American Dietetic Association, and are only able to use the title "dietitian", as described by the business and professions codes of each respective state, when they have met specific educational and experiential prerequisites and passed a national registration or licensure examination, respectively. Anyone may call themselves a nutritionist, including unqualified dietitians, as this term is unregulated.{{Citation needed|date=June 2019}} Some states, such as the State of Florida, have begun to include the title "nutritionist" in state licensure requirements. Most governments provide guidance on nutrition, and some also impose [[mandatory labeling|mandatory disclosure/labeling]] requirements for processed food manufacturers and restaurants to assist consumers in complying with such guidance.{{citation needed|date=July 2015}}

Nutritional standards and recommendations are established jointly by the [[USDA|US Department of Agriculture]] and [[United States Department of Health and Human Services|US Department of Health and Human Services]].<ref name="TODAY.com 2020 r293">{{cite web | last=Breen | first=Kerry | title=USDA releases new dietary guidelines: What do they mean for you? | website=TODAY.com | date=December 29, 2020 | url=https://www.today.com/health/usda-hhs-releases-new-dietary-guidelines-2020-2025-t204784 | access-date=April 8, 2024}}</ref> Dietary and physical activity guidelines from the USDA are presented in the concept of a [[MyPlate|plate of food]] which in 2011 superseded the [[MyPyramid]] food pyramid that had replaced the [[History of USDA nutrition guidelines#Food Guide Pyramid|Food Guide Pyramid]].<ref name="The Nutrition Source 2011 f036">{{cite web | title=Out with the Pyramid, In with the Plate | website=[[Harvard T.H. Chan School of Public Health]] | date=June 3, 2011 | url=https://www.hsph.harvard.edu/nutritionsource/2011/06/03/out-with-the-pyramid-in-with-the-plate/ | access-date=April 8, 2024}}</ref> The [[United States Senate Committee on Agriculture, Nutrition, and Forestry]] is currently responsible for oversight of the USDA.<ref name="Goldstein 2023 w035">{{cite web | last=Goldstein | first=Adam | title=Members of U.S. Senate agriculture panel spar with Vilsack over USDA spending, response • Missouri Independent | website=Missouri Independent | date=March 17, 2023 | url=https://missouriindependent.com/2023/03/17/members-of-u-s-senate-agriculture-panel-spar-with-vilsack-over-usda-spending-response/ | access-date=April 8, 2024}}</ref> The [[U.S. Department of Health and Human Services]] provides a sample week-long menu which fulfills the nutritional recommendations of the government.<ref>{{cite web | url=http://www.mypyramid.gov/downloads/sample_menu.pdf | title=Archived copy | access-date=8 March 2008 | url-status=dead | archive-url=https://web.archive.org/web/20080308032337/http://www.mypyramid.gov/downloads/sample_menu.pdf | archive-date=8 March 2008}}</ref>

==== Canada ====
[[Canada's Food Guide]] is an evidence-based education and policy tool provided by [[Health Canada]] that is designed to promote healthy eating.<ref name="UN_Canada">{{cite web | title=Food-based dietary guidelines – Canada | website=Food and Agriculture Organization of the United Nations | url=https://www.fao.org/nutrition/education/food-dietary-guidelines/regions/countries/canada/en/ | access-date=April 8, 2024}}</ref>

=== South Asia ===
[[South Asia]] has the highest percentage and number of underweight children under five in the world, at approximately 78 million children.<ref name="Progress for Children" /> Patterns of stunting and wasting are similar, where 44% have not reached optimal height and 15% are wasted, rates much higher than any other regions.<ref name="Progress for Children" /> This region of the world has extremely high rates of underweight children. According to a 2006 UNICEF study, 46% of its child population under five is underweight.<ref name="Progress for Children" /> The same study indicates India, Bangladesh, and Pakistan combined account for half the globe's underweight child population.<ref name="Progress for Children" /> South Asian nations have made progress towards the [[MDGs]], considering the rate has decreased from 53% since 1990, however, a 1.7% decrease of underweight prevalence per year will not be sufficient to meet the 2015 goal.<ref name="Progress for Children" /> Some nations, such as [[Afghanistan]], [[Bangladesh]], and [[Sri Lanka]], on the other hand, have made significant improvements, all decreasing their prevalence by half in ten years.<ref name="Progress for Children" /> While [[India]] and [[Pakistan]] have made modest improvements, [[Nepal]] has made no significant improvement in underweight child prevalence.<ref name="Progress for Children" /> Other forms of undernutrition have continued to persist with high resistance to improvement, such as the prevalence of stunting and wasting, which has not changed significantly in the past 10 years.<ref name="Progress for Children" /> Causes of this poor nutrition include energy-insufficient diets, poor sanitation conditions, and the gender disparities in educational and social status.<ref name="Progress for Children" /> Girls and women face discrimination especially in nutrition status, where South Asia is the only region in the world where girls are more likely to be underweight than boys.<ref name="Progress for Children" /> In South Asia, 60% of children in the lowest quintile are underweight, compared to only 26% in the highest quintile, and the rate of reduction of underweight is slower amongst the poorest.<ref name="UNMDG2011">UN (2011b). The Millennium Development Goals report 2011. New York, United Nations. http://www.un.org/en/development/desa/news/statistics/mdg-report-2011.html {{Webarchive|url=https://web.archive.org/web/20221006011330/http://www.un.org/en/development/desa/news/statistics/mdg-report-2011.html |date=2022-10-06 }}.</ref>

=== Eastern and Southern Africa ===
The Eastern and Southern African nations have shown no improvement since 1990 in the rate of underweight children under five.<ref name="Progress for Children" /> They have also made no progress in halving hunger by 2015, the most prevalent [[Millennium Development Goal]].<ref name="Progress for Children" /> This is due primarily to the prevalence of famine, declined agricultural productivity, food emergencies, drought, conflict, and increased poverty.<ref name="Progress for Children" /> This, along with [[HIV]]/[[AIDS]], has inhibited the nutrition development of nations such as [[Lesotho]], [[Malawi]], [[Mozambique]], [[Swaziland]], [[Zambia]] and [[Zimbabwe]].<ref name="Progress for Children" /> [[Botswana]] has made remarkable achievements in reducing underweight prevalence, dropping 4% in 4 years, despite its place as the second leader in HIV prevalence amongst adults in the globe.<ref name="Progress for Children" /> [[South Africa]], the wealthiest nation in this region, has the second-lowest proportion of underweight children at 12%, but has been steadily increasing in underweight prevalence since 1995.<ref name="Progress for Children" /> Almost half of [[Ethiopian]] children are underweight, and along with [[Nigeria]], they account for almost one-third of the underweight under five in all of [[Sub-Saharan Africa]].<ref name="Progress for Children" />

=== West and Central Africa ===
[[West Africa|West]] and [[Central Africa|Central]] Africa has the highest rate of children under five underweight in the world.<ref name="Progress for Children" /> Of the countries in this region, the Congo has the lowest rate at 14%, while the nations of [[Democratic Republic of the Congo]], [[Ghana]], [[Guinea]], [[Mali]], [[Nigeria]], [[Senegal]] and [[Togo]] are improving slowly.<ref name="Progress for Children" /> In [[Gambia]], rates decreased from 26% to 17% in four years, and their coverage of vitamin A supplementation reaches 91% of vulnerable populations.<ref name="Progress for Children" /> This region has the next highest proportion of wasted children, with 10% of the population under five not at optimal weight.<ref name="Progress for Children" /> Little improvement has been made between the years of 1990 and 2004 in reducing the rates of underweight children under five, whose rate stayed approximately the same.<ref name="Progress for Children" /> [[Sierra Leone]] has the highest child under five mortality rate in the world, due predominantly to its extreme infant mortality rate, at 238 deaths per 1000 live births.<ref name="Progress for Children" /> Other contributing factors include the high rate of low birthweight children (23%) and low levels of exclusive breast feeding (4%).<ref name="Progress for Children" /> Anemia is prevalent in these nations, with unacceptable rates of iron deficient anemia.<ref name="Progress for Children" /> The nutritional status of children is further indicated by its high (10%) rate of child wasting.<ref name="Progress for Children" /> Wasting is a significant problem in Sahelian countries&nbsp;– [[Burkina Faso]], [[Chad]], [[Mali]], [[Mauritania]] and [[Niger]]&nbsp;– where rates fall between 11% and 19% of under fives, affecting more than 1 million children.<ref name="Progress for Children" />

In [[Mali]], the [[International Crops Research Institute for the Semi-Arid Tropics]] ([[ICRISAT]]) and the [[Aga Khan Foundation]] trained women's groups to make ''equinut'', a healthy and nutritional version of the traditional recipe ''di-dèguè'' (comprising peanut paste, honey and millet or rice flour). The aim was to boost nutrition and livelihoods by producing a product that women could make and sell, and which would be accepted by the local community because of its local heritage.<ref>[http://www.impatientoptimists.org/Posts/2013/04/Nourishing-Communities-Through-Holistic-Farming ''Nourishing communities through holistic farming''] {{Webarchive|url=https://web.archive.org/web/20181006235945/https://www.impatientoptimists.org/Posts/2013/04/Nourishing-Communities-Through-Holistic-Farming |date=6 October 2018 }}, Impatient optimists, [[Bill & Melinda Gates Foundation]]. 30 April 2013.</ref>

=== Middle East and North Africa ===
Six countries in the [[Middle East]] and [[North Africa]] region are on target to meet goals for reducing underweight children by 2015, and 12 countries have prevalence rates below 10%.<ref name="Progress for Children" /> However, the nutrition of children in the region as a whole has degraded for the past ten years due to the increasing portion of underweight children in three populous nations&nbsp;– [[Iraq]], [[Sudan]], and [[Yemen]].<ref name="Progress for Children" /> Forty six percent of all children in [[Yemen]] are underweight, a percentage that has worsened by 4% since 1990.<ref name="Progress for Children" /> In Yemen, 53% of children under five are stunted and 32% are born at low birth weight.<ref name="Progress for Children" /> Sudan has an underweight prevalence of 41%, and the highest proportion of wasted children in the region at 16%.<ref name="Progress for Children" /> One percent of households in Sudan consume iodized salt.<ref name="Progress for Children" /> Iraq has also seen an increase in child underweight since 1990.<ref name="Progress for Children" /> [[Djibouti]], [[Jordan]], the [[Occupied Palestinian Territory]] (OPT), [[Oman]], the [[Syrian Arab Republic]] and [[Tunisia]] are all projected to meet minimum nutrition goals, with OPT, Syrian AR, and Tunisia the fastest improving regions.<ref name="Progress for Children" /> This region demonstrates that undernutrition does not always improve with economic prosperity, where the [[United Arab Emirates]], for example, despite being a wealthy nation, has similar child death rates due to malnutrition to those seen in [[Yemen]].<ref name="Progress for Children" />

=== East Asia and the Pacific ===
The [[East Asia]] and Pacific region has reached its goals on nutrition, in part due to the improvements contributed by [[China]], the region's most populous country.<ref name="Progress for Children" /> China has reduced its underweight prevalence from 19 percent to 8 percent between 1990 and 2002.<ref name="Progress for Children" /> China played the largest role in the world in decreasing the rate of children under five underweight between 1990 and 2004, halving the prevalence.<ref name="Progress for Children" /> This reduction of underweight prevalence has aided in the lowering of the under 5 mortality rate from 49 to 31 of 1000. They also have a low birthweight rate at 4%, a rate comparable to industrialized countries, and over 90% of households receive adequate iodized salts.<ref name="Progress for Children" /> However, large disparities exist between children in rural and urban areas, where 5 provinces in China leave 1.5 million children iodine deficient and susceptible to diseases.<ref name="Progress for Children" /> [[Singapore]], [[Vietnam]], [[Malaysia]], and [[Indonesia]] are all projected to reach nutrition MDGs.<ref name="Progress for Children" /> [[Singapore]] has the lowest under five mortality rate of any nation, besides [[Iceland]], in the world, at 3%.<ref name="Progress for Children" /> [[Cambodia]] has the highest rate of child mortality in the region (141 per 1,000 live births), while still its proportion of underweight children increased by 5 percent to 45% in 2000. Further nutrient indicators show that only 12 per cent of Cambodian babies are exclusively breastfed and only 14 per cent of households consume [[iodized salt]].<ref name="Progress for Children" />

=== Latin America and the Caribbean ===
This region has undergone the fastest progress in decreasing poor nutrition status of children in the world.<ref name="Progress for Children" /> The [[Latin American]] region has reduced underweight children prevalence by 3.8% every year between 1990 and 2004, with a current rate of 7% underweight.<ref name="Progress for Children" /> They also have the lowest rate of child mortality in the developing world, with only 31 per 1000 deaths, and the highest [[iodine]] consumption.<ref name="Progress for Children" /> [[Cuba]] has seen improvement from 9 to 4 percent underweight under 5 between 1996 and 2004.<ref name="Progress for Children" /> The prevalence has also decreased in the [[Dominican Republic]], [[Jamaica]], [[Peru]], and [[Chile]].<ref name="Progress for Children" /> Chile has a rate of underweight under 5, at merely 1%.<ref name="Progress for Children" /> The most populous nations, [[Brazil]] and [[Mexico]], mostly have relatively low rates of underweight under 5, with only 6% and 8%.<ref name="Progress for Children" /> [[Guatemala]] has the highest percentage of underweight and stunted children in the region, with rates above 45%.<ref name="Progress for Children" /> There are disparities amongst different populations in this region. For example, children in rural areas have twice the prevalence of underweight at 13%, compared to urban areas at 5%.<ref name="Progress for Children" />

== Nutrition access disparities ==
Occurring throughout the world, lack of proper nutrition is both a consequence and cause of poverty.<ref name="Progress for Children" /> Impoverished individuals are less likely to have access to nutritious food and to escape from poverty than those who have healthy diets.<ref name="Progress for Children" /> Disparities in [[socioeconomic]] status, both between and within nations, provide the largest threat to child nutrition in industrialized nations, where social inequality is on the rise.<ref name=P4C43>{{cite web | title=World Health Organization, European Health Report 2005: Public health action for healthier children and populations | publisher=WHO Regional Office for Europe, Copenhagen | date=2005 | url=http://www.euro.who.int/__data/assets/pdf_file/0004/82435/E87325.pdf?ua=1 | access-date=2014-12-15 | archive-date=2016-03-04 | archive-url=https://web.archive.org/web/20160304035801/http://www.euro.who.int/__data/assets/pdf_file/0004/82435/E87325.pdf?ua=1 | url-status=live}}</ref> According to UNICEF, children living in the poorest households are twice as likely to be [[underweight]] as those in the richest.<ref name="Progress for Children" /> Those in the lowest wealth [[Household income in the United States#Quintiles|quintile]] and whose mothers have the least education demonstrate the highest rates of child mortality and [[stunted growth|stunting]].<ref name="WHOstats">{{cite web | title=WHO (2013b) | publisher=World health statistics. Geneva, World Health Organization | url=https://www.who.int/iris/bitstream/10665/81965/1/9789241564588_eng.pdf | archive-url=https://web.archive.org/web/20130616210234/http://www.who.int/iris/bitstream/10665/81965/1/9789241564588_eng.pdf | archive-date=2013-06-16 | url-status=live}}</ref> Throughout the developing world, socioeconomic inequality in childhood malnutrition is more severe than in upper income brackets, regardless of the general rate of malnutrition.<ref name="VanP">{{cite journal | vauthors=Van de Poel E, Hosseinpoor AR, Speybroeck N, Van Ourti T, Vega J | title=Socioeconomic inequality in malnutrition in developing countries | journal=Bulletin of the World Health Organization | volume=86 | issue=4 | pages=282–91 | date=April 2008 | pmid=18438517 | pmc=2647414 | doi=10.2471/blt.07.044800}}</ref>
According to UNICEF, children in rural locations are more than twice as likely to be underweight as compared to children under five in urban areas.<ref name="Progress for Children" /> In Latin American/Caribbean nations, "Children living in rural areas in Bolivia, Honduras, Mexico and Nicaragua are more than twice as likely to be underweight as children living in urban areas. That likelihood doubles to four times in Peru." Concurrently, the greatest increase in [[childhood obesity]] has been seen in the lower middle income bracket.<ref name="WHOglobe">{{cite web | title=WHO (2011a). Global status report on noncommunicable diseases 2010 | publisher=Geneva, World Health Organization | url=https://www.who.int/nmh/publications/ncd_report2010/en/index.html | archive-url=https://web.archive.org/web/20110502141545/http://www.who.int/nmh/publications/ncd_report2010/en/index.html | url-status=dead | archive-date=2 May 2011}}</ref>

In the United States, the incidence of low birthweight is on the rise among all populations, but particularly among [[minorities]].<ref name=P4C45>{{cite web | vauthors=Polhamus B, etal | title=Pediatric Nutrition Surveillance 2003 Report, Table 18D | publisher=U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Atlanta | date=2004 | url=https://www.cdc.gov/pednss/pednss_tables/pdf/national_table18.pdf | archive-url=https://web.archive.org/web/20041117002747/http://www.cdc.gov/pednss/pednss_tables/pdf/national_table18.pdf | archive-date=2004-11-17 | url-status=live}}</ref>

According to UNICEF, boys and girls have almost identical rates as underweight children under age 5 across the world, except in [[South Asia]].<ref name="Progress for Children" />

== Nutrition policy ==
=== Nutrition interventions ===
Nutrition directly influences progress towards meeting the [[Millennium Development Goals]] of eradicating hunger and poverty through health and education.<ref name="Progress for Children" /> Therefore, nutrition interventions take a multi-faceted approach to improve the nutrition status of various populations. Policy and programming must target both individual behavioral changes and policy approaches to public health. While most nutrition interventions focus on delivery through the health-sector, non-health sector interventions targeting [[agriculture]], water and sanitation, and education are important as well.<ref name="Essential Nutrition Actions" /> Global nutrition [[Micronutrient deficiency|micronutrient deficiencies]] often receive large-scale solution approaches by deploying large governmental and non-governmental organizations. For example, in 1990, [[iodine deficiency]] was particularly prevalent, with one in five households, or 1.7 billion people, not consuming adequate iodine, leaving them at risk to develop associated diseases.<ref name="Progress for Children" /> Therefore, a global campaign to iodize salt to eliminate iodine deficiency successfully boosted the rate to 69% of households in the world consuming adequate amounts of iodine.<ref name="Progress for Children" />

Emergencies and crises often exacerbate undernutrition, due to the aftermath of crises that include food insecurity, poor health resources, unhealthy environments, and poor healthcare practices.<ref name="Progress for Children" /> Therefore, the repercussions of natural disasters and other emergencies can exponentially increase the rates of macro and micronutrient deficiencies in populations.<ref name="Progress for Children" /> Disaster relief interventions often take a multi-faceted public health approach. UNICEF's programming targeting nutrition services amongst disaster settings include nutrition assessments, [[measles]] immunization, vitamin A supplementation, provision of fortified foods and micronutrient supplements, support for breastfeeding and complementary feeding for infants and young children, and therapeutic and supplementary feeding.<ref name="Progress for Children" /> For example, during Nigeria's food crisis of 2005, 300,000 children received therapeutic nutrition feeding programs through the collaboration of [[UNICEF]], the [[Niger]] government, the [[World Food Programme]], and 24 NGOs utilizing community and facility based feeding schemes.<ref name="Progress for Children" />

Interventions aimed at pregnant women, infants, and children take a behavioral and program-based approach. Behavioral intervention objectives include promoting proper breast-feeding, the immediate initiation of breastfeeding, and its continuation through 2 years and beyond.<ref name="Essential Nutrition Actions" /> UNICEF recognizes that to promote these behaviors, healthful environments must be established conducive to promoting these behaviors, like healthy hospital environments, skilled health workers, support in the public and workplace, and removing negative influences.<ref name="Essential Nutrition Actions" /> Finally, other interventions include provisions of adequate micro and macro nutrients such as iron, anemia, and vitamin A supplements and vitamin-fortified foods and ready-to-use products.<ref name="Essential Nutrition Actions" /> Programs addressing [[micronutrient deficiencies]], such as those aimed at anemia, have attempted to provide iron supplementation to pregnant and lactating women. However, because supplementation often occurs too late, these programs have had little effect.<ref name="Progress for Children" /> Interventions such as women's nutrition, early and exclusive breastfeeding, appropriate complementary food and micronutrient supplementation have proven to reduce stunting and other manifestations of undernutrition.<ref name="IMPROVING CHILD NUTRITION" /> A Cochrane review of community-based maternal health packages showed that this community-based approach improved the initiation of breastfeeding within one hour of birth.<ref>{{cite journal | vauthors=Lassi ZS, Bhutta ZA | title=Community-based intervention packages for reducing maternal and neonatal morbidity and mortality and improving neonatal outcomes | journal=The Cochrane Database of Systematic Reviews | issue=3 | pages=CD007754 | date=March 2015 | volume=2015 | pmid=25803792 | doi=10.1002/14651858.CD007754.pub3 | pmc=8498021 | url=https://ecommons.aku.edu/cgi/viewcontent.cgi?article=1007&context=pakistan_fhs_mc_women_childhealth_wc | access-date=2019-09-24 | archive-date=2022-03-09 | archive-url=https://web.archive.org/web/20220309043003/https://ecommons.aku.edu/cgi/viewcontent.cgi?article=1007&context=pakistan_fhs_mc_women_childhealth_wc | url-status=live}}</ref> Some programs have had adverse effects. One example is the "Formula for Oil" relief program in Iraq, which resulted in the replacement of breastfeeding for formula, which has negatively affected infant nutrition.<ref name="Progress for Children" />

=== Implementation and delivery platforms ===
In April 2010, the World Bank and the IMF released a policy briefing entitled "Scaling up Nutrition (SUN): A Framework for action" that represented a partnered effort to address the Lancet's Series on under nutrition, and the goals it set out for improving under nutrition.<ref name="SUN">{{cite journal | vauthors=Nabarro D | title=Global child and maternal nutrition--the SUN rises | journal=Lancet | volume=382 | issue=9893 | pages=666–7 | date=August 2013 | pmid=23746773 | doi=10.1016/S0140-6736(13)61086-7 | s2cid=34484370}}</ref> They emphasized the 1000 days after birth as the prime window for effective nutrition intervention, encouraging programming that was cost-effective and showed significant cognitive improvement in populations, as well as enhanced productivity and economic growth.<ref name="SUN" /> This document was labeled the SUN framework, and was launched by the [[UN General Assembly]] in 2010 as a road map encouraging the coherence of stakeholders like governments, [[academia]], UN system organizations and foundations in working towards reducing under nutrition.<ref name="SUN" /> The SUN framework has initiated a transformation in global nutrition- calling for country-based nutrition programs, increasing evidence based and cost–effective interventions, and "integrating nutrition within national strategies for [[gender equality]], agriculture, [[food security]], [[social protection]], education, water supply, sanitation, and health care".<ref name="SUN" /> Government often plays a role in implementing nutrition programs through policy. For instance, several East Asian nations have enacted legislation to increase iodization of salt to increase household consumption.<ref name="Progress for Children" /> Political commitment in the form of evidence-based effective national policies and programs, trained skilled community nutrition workers, and effective communication and advocacy can all work to decrease malnutrition.<ref name="IMPROVING CHILD NUTRITION" /> Market and industrial production can play a role as well. For example, in the [[Philippines]], improved production and market availability of iodized salt increased household consumption.<ref name="Progress for Children" /> While most nutrition interventions are delivered directly through governments and health services, other sectors, such as agriculture, water and sanitation, and education, are vital for nutrition promotion as well.<ref name="Essential Nutrition Actions" />

== Advice and guidance ==
=== Government policies ===
[[File:MyPlate Game.jpg|thumb|MyPlate Game]]
[[Canada's Food Guide]] is an example of a government-run nutrition program. Produced by [[Health Canada]], the guide advises food quantities, provides education on balanced nutrition, and promotes physical activity in accordance with government-mandated nutrient needs. Like other nutrition programs around the world, Canada's Food Guide divides nutrition into four main food groups: vegetables and fruit, grain products, milk and alternatives, and meat and alternatives.<ref>[https://web.archive.org/web/20170612160554/http://www.hc-sc.gc.ca/fn-an/food-guide-aliment/index-eng.php Canada's Food Guide]. Health Canada</ref> Unlike its American counterpart, the Canadian guide references and provides alternative to meat and dairy, which can be attributed to the growing [[vegan]] and [[vegetarian]] movements.

In the US, nutritional standards and recommendations are established jointly by the [[USDA|US Department of Agriculture]] and [[United States Department of Health and Human Services|US Department of Health and Human Services]] (HHS) and these recommendations are published as the [[Dietary Guidelines for Americans]]. Dietary and physical activity guidelines from the USDA are presented in the concept of [[MyPlate]], which superseded the [[MyPyramid|food pyramid]], which replaced the [[Four Food Groups]]. The Senate committee currently responsible for oversight of the USDA is the ''Agriculture, Nutrition and Forestry Committee''. Committee hearings are often televised on [[C-SPAN]]. The U.S. HHS provides a sample week-long menu that fulfills the nutritional recommendations of the government.<ref>[https://web.archive.org/web/20080308032337/http://www.mypyramid.gov/downloads/sample_menu.pdf Sample Menus for a 2000 Calorie Food Pattern]. mypyramid.gov</ref>

=== Government programs ===
Governmental organisations have been working on nutrition literacy interventions in non-primary health care settings to address the nutrition information problem in the U.S. Some programs include:

The Family Nutrition Program (FNP) is a free nutrition education program serving low-income adults around the U.S. This program is funded by the Food Nutrition Service's (FNS) branch of the United States Department of Agriculture (USDA) usually through a local state academic institution that runs the program. The FNP has developed a series of tools to help families participating in the [[Food stamp program|Food Stamp Program]] stretch their food dollar and form healthful eating habits including nutrition education.<ref>{{Cite journal | last1=Guthrie | first1=Joanne F. | last2=Stommes | first2=Eileen | last3=Voichick | first3=Jane | date=January–February 2006 | title=Evaluating Food Stamp Nutrition Education: Issues and Opportunities | url=https://www.jneb.org/article/S1499-4046(05)00003-5/fulltext | journal=Journal of Nutrition Education and Behavior | volume=38 | issue=1 | pages=6–11 | doi=10.1016/j.jneb.2005.11.001 | pmid=16595272 | access-date=2020-01-03 | archive-date=2022-01-25 | archive-url=https://web.archive.org/web/20220125210911/https://www.jneb.org/article/S1499-4046(05)00003-5/fulltext | url-status=live}}</ref>

[https://web.archive.org/web/20111118025724/http://www.csrees.usda.gov/nea/food/efnep/efnep.html Expanded Food and Nutrition Education Program] (ENFEP) is a unique program that currently operates in all 50 states and in [[American Samoa]], [[Guam]], [[Micronesia]], [[Northern Mariana Islands]], [[Puerto Rico]], and the [[Virgin Islands]]. It is designed to assist limited-resource audiences in acquiring the knowledge, skills, attitudes, and changed behavior necessary for nutritionally sound diets, and to contribute to their personal development and the improvement of the total family diet and nutritional well-being.

An example of a state initiative to promote nutrition literacy is [https://web.archive.org/web/20120221061109/http://www.smartbodies.org/smart-bodies Smart Bodies], a public-private partnership between the state's largest university system and largest health insurer, Louisiana State Agricultural Center and Blue Cross and Blue Shield of Louisiana Foundation. Launched in 2005, this program promotes lifelong healthful eating patterns and physically active lifestyles for children and their families. It is an interactive educational program designed to help prevent childhood obesity through classroom activities that teach children healthful eating habits and physical exercise.

=== Education ===
{{Main|Nutrition education|Food studies#Food and education}}

Nutrition is taught in schools in many countries. In [[England and Wales]], the [[Personal and social education|Personal and Social Education]] and Food Technology curricula include nutrition, stressing the importance of a balanced diet and teaching how to read nutrition labels on packaging. In many schools, a Nutrition class will fall within the Family and Consumer Science (FCS) or Health departments. In some American schools, students are required to take a certain number of FCS or Health related classes. Nutrition is offered at many schools, and, if it is not a class of its own, nutrition is included in other FCS or Health classes such as: Life Skills, Independent Living, Single Survival, Freshmen Connection, Health etc. In many Nutrition classes, students learn about the food groups, the food pyramid, Daily Recommended Allowances, calories, vitamins, minerals, malnutrition, physical activity, healthful food choices, portion sizes, and how to live a healthy life.<ref>{{Cite journal | last=Rizvi | first=DaliyaS | date=2022 | title=Health education and global health: Practices, applications, and future research | journal=Journal of Education and Health Promotion | language=en | volume=11 | issue=1 | pages=262 | doi=10.4103/jehp.jehp_218_22 | doi-access=free | issn=2277-9531 | pmc=9621358 | pmid=36325224}}</ref>

A 1985 US [[United States National Research Council|National Research Council]] report entitled ''Nutrition Education in US Medical Schools'' concluded that nutrition education in medical schools was inadequate.<ref name="p. 4">Commission on Life Sciences. (1985). ''Nutrition Education in US Medical Schools'', [http://books.nap.edu/openbook.php?record_id=597&page=4 p. 4] {{Webarchive|url=https://web.archive.org/web/20110607120934/http://books.nap.edu/openbook.php?record_id=597&page=4 |date=2011-06-07 }}. National Academies Press.</ref> Only 20% of the schools surveyed taught nutrition as a separate, required course. A 2006 survey found that this number had risen to 30%.<ref>{{cite journal | vauthors=Adams KM, Lindell KC, Kohlmeier M, Zeisel SH | title=Status of nutrition education in medical schools | journal=Am. J. Clin. Nutr. | volume=83 | issue=4 | pages=941S–14S | year=2006 | pmid=16600952 | pmc=2430660 | doi=10.1093/ajcn/83.4.941S}}</ref> Membership by physicians in leading professional nutrition societies such as the [[American Society for Nutrition]] has generally declined from the 1990s.<ref>{{cite journal | last1=McClave | first1=Stephen A. | last2=Mechanick | first2=Jeffrey I. | last3=Bistrian | first3=Bruce | last4=Graham | first4=Toby | last5=Hegazi | first5=Refaat | last6=Jensen | first6=Gordon L. | last7=Kushner | first7=Robert F. | last8=Merritt | first8=Russell | date=1 December 2016 | title=What is the significance of a physician shortage in nutrition medicine? | journal=Journal of Parenteral and Enteral Nutrition | volume=34 | issue=6 Suppl | pages=7S–20S | doi=10.1177/0148607110375429 | pmid=21149831}}</ref>

=== Professional organizations ===
In the US, [[Dietitian|Registered dietitian nutritionists]] (RDs or RDNs)<ref>{{cite web | title=What is an RDN and DTR? | url=http://www.eatrightpro.org/resources/about-us/what-is-an-rdn-and-dtr | publisher=Academy of Nutrition and Dietetics | access-date=9 May 2015 | archive-date=23 December 2017 | archive-url=https://web.archive.org/web/20171223114300/http://www.eatrightpro.org/resources/about-us/what-is-an-rdn-and-dtr | url-status=dead}}</ref> are [[health professionals]] qualified to provide safe, evidence-based dietary advice which includes a review of what is [[Eating|eaten]], a thorough review of nutritional health, and a personalized nutritional treatment plan through [[dieting]]. They also provide preventive and therapeutic programs at work places, schools and similar institutions. Certified Clinical [[Nutritionist]]s or CCNs, are trained health professionals who also offer dietary advice on the role of nutrition in chronic disease, including possible prevention or remediation by addressing nutritional deficiencies before resorting to drugs.<ref>http://www.iaacn.org/ {{Webarchive|url=https://web.archive.org/web/20221204212840/https://iaacn.org/ |date=2022-12-04 }} The International & American Associations of Clinical Nutritionist, 2014, Retrieved 14 December 2014</ref> Government regulation especially in terms of licensing, is currently less universal for the CCN than that of RD or RDN. Another advanced Nutrition Professional is a Certified Nutrition Specialist or CNS. These Board Certified Nutritionists typically specialize in [[obesity]] and [[chronic disease]]. In order to become board certified, potential CNS candidate must pass an examination, much like Registered Dieticians. This exam covers specific domains within the health sphere including; Clinical Intervention and Human Health.<ref>{{Cite web | title=FAQs about CNS Certification – Certification Board for Nutrition Specialists | url=http://cbns.org/faqs-cns-certification/ | access-date=24 September 2015 | archive-date=11 August 2014 | archive-url=https://web.archive.org/web/20140811170414/http://cbns.org/faqs-cns-certification/ | url-status=live}}</ref> The [[National Board of Physician Nutrition Specialists]] offers board certification for physicians practicing nutrition medicine.<ref>{{cite journal | last1=Van Horn | first1=L | last2=Lenders | first2=CM | last3=Pratt | first3=CA | last4=Beech | first4=B | last5=Carney | first5=PA | last6=Dietz | first6=W | last7=DiMaria-Ghalili | first7=R | last8=Harlan | first8=T | last9=Hash | first9=R |last10=Kohlmeier |first10=M | last11=Kolasa | first11=K | last12=Krebs | first12=NF | last13=Kushner | first13=RF | last14=Lieh-Lai | first14=M | last15=Lindsley | first15=J | last16=Meacham | first16=S | last17=Nicastro | first17=H | last18=Nowson | first18=C | last19=Palmer | first19=C |last20=Paniagua |first20=M | last21=Philips | first21=E | last22=Ray | first22=S | last23=Rose | first23=S | last24=Salive | first24=M | last25=Schofield | first25=M | last26=Thompson | first26=K | last27=Trilk | first27=JL | last28=Twillman | first28=G | last29=White | first29=JD |last30=Zappalà |first30=G | last31=Vargas | first31=A | last32=Lynch | first32=C | title=Advancing Nutrition Education, Training, and Research for Medical Students, Residents, Fellows, Attending Physicians, and Other Clinicians: Building Competencies and Interdisciplinary Coordination. | journal=Advances in Nutrition | date=1 November 2019 | volume=10 | issue=6 | pages=1181–1200 | doi=10.1093/advances/nmz083 | pmid=31728505 | pmc=6855992 | doi-access=free}}</ref>

== Nutrition for special populations ==
=== Sports nutrition ===
{{Main|Sports nutrition}}

The protein requirement for each individual differs, as do opinions about whether and to what extent physically active people require more protein. The 2005 [[Recommended Dietary Allowance]]s (RDA), aimed at the general healthy adult population, provide for an intake of 0.8 grams of protein per kilogram of body weight.<ref name="DRI" /> A review panel stating that "no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise".<ref>{{cite book | last=Di Pasquale | first=Mauro G. | title=Sports Nutrition: Energy metabolism and exercise | editor=Ira Wolinsky, Judy A. Driskell | publisher=CRC Press | year=2008 | page=73 | chapter=Utilization of Proteins in Energy Metabolism | author-link=Mauro Di Pasquale | isbn=978-0-8493-7950-5}}</ref>

The main fuel used by the body during exercise is carbohydrates, which is stored in muscle as glycogen&nbsp;– a form of sugar. During exercise, muscle glycogen reserves can be used up, especially when activities last longer than 90&nbsp;min.<ref>{{Cite web | url=http://www.extension.iastate.edu/humansciences/content/carbohydrate | title=Iowa State University: Extension and outreach | access-date=2015-04-16 | archive-date=2015-04-19 | archive-url=https://web.archive.org/web/20150419024429/http://www.extension.iastate.edu/humansciences/content/carbohydrate | url-status=dead}}</ref>

=== Maternal nutrition ===
{{Main|Nutrition and pregnancy}}Maternal nutrition is crucial during pregnancy and the child's first 1,000 days of life, encompassing the period from conception to the second birthday. During the first six months, infants rely exclusively on breast milk, which remains nutritionally sufficient despite maternal nutritional challenges.<ref name="likhar-2022">{{Cite journal | last1=Likhar | first1=Akanksha | last2=Patil | first2=Manoj S | date=2022-10-08 | title=Importance of Maternal Nutrition in the First 1,000 Days of Life and Its Effects on Child Development: A Narrative Review | journal=Cureus | volume=14 | issue=10 | pages=e30083 | language=en | doi=10.7759/cureus.30083 | doi-access=free | issn=2168-8184 | pmc=9640361 | pmid=36381799}}</ref> However, the mother's overall health and diet directly impact the child's well-being. The importance of maternal nutrition is a critical influence on a child's development during this pivotal period, as supported by recent studies. The child's growth is divided into four key stages: (1) pregnancy, from conception to birth; (2) breastfeeding, from birth to six months; (3) the introduction of solid foods, from six to 12 months; and (4) the transition to a family diet after 12 months, with each stage requiring specific nutritional considerations for optimal development. Additionally, there is a significant connection between nutrition, overall health, and learning, with proper nutritional intake being vital for maintaining healthy body weight and supporting normal growth during infancy, childhood, and adolescence.<ref name="likhar-2022" /> Given the rapid growth during infancy, this phase demands the highest relative energy and nutrient intake compared to other stages of development.

Proper nutrition during pregnancy plays a vital role in the development of the brain, requiring essential nutrients such as specific [[lipid]]s, [[Protein (nutrient)|protein]], [[folate]], [[zinc]], [[iodine]], [[Iron (nutrient)|iron]], and [[Copper deficiency|copper]]. Ensuring that children receive adequate nutrition during the first 1,000 days—from conception to the second birthday—significantly increases their chances of being born at a healthy weight. Additionally, it lowers the risk of various health conditions, including obesity and type 2 diabetes, while also fostering better learning abilities, fewer behavioral issues during early childhood, and improved overall health and economic stability in the long term.<ref name="likhar-2022" />

=== Pediatric nutrition ===
Adequate nutrition is essential for the growth of children from infancy right through until adolescence. Some nutrients are specifically required for growth on top of nutrients required for normal body maintenance, in particular [[Calcium metabolism|calcium]] and [[Human iron metabolism|iron metabolism]].<ref>{{Cite book | title=Food and Nutrition: Food and Health Systems in Australia and New Zealand | last=Wahlqvist | first=M. L. | publisher=Allen & Unwin | year=2011 | isbn=978-1-74175-897-9 | location=NSW, Australia | pages=429–441 | edition=3rd}}</ref> Childhood dietary patterns are influenced by various factors, including feeding challenges and nutritional needs, with significant long-term consequences. During the first year, an infant's birth weight triples, and by age five, their birth length doubles. Brain volume doubles within the first 12 months and triples by 36 months. To support this rapid growth, solid foods are introduced after six months to supplement [[breast milk]] or [[infant formula]].<ref>{{Cite journal | last1=Scaglioni | first1=Silvia | last2=De Cosmi | first2=Valentina | last3=Mazzocchi | first3=Alessandra | date=2022-06-30 | title=Nutritional Habits and Interventions in Childhood | journal=Nutrients | language=en | volume=14 | issue=13 | pages=2730 | doi=10.3390/nu14132730 | doi-access=free | issn=2072-6643 | pmc=9268943 | pmid=35807910}}</ref> As children begin to consume more table foods in their second year, they are exposed to the same diet as their caregivers, which, along with more complex food combinations, shapes their dietary habits by 24 months. Imbalances in diet during this critical period can lead to [[malnutrition]], with the highest risk occurring around the time of [[weaning]], typically at 12 months in the U.S. and later in the second year globally. As a child transitions from breast milk or formula, dairy milk often becomes a key nutritional source, making the quality of the diet essential for continued growth and development.<ref name="reverri-2022">{{Cite journal | last1=Reverri | first1=Elizabeth J. | last2=Arensberg | first2=Mary Beth | last3=Murray | first3=Robert D. | last4=Kerr | first4=Kirk W. | last5=Wulf | first5=Karyn L. | date=2022-07-28 | title=Young Child Nutrition: Knowledge and Surveillance Gaps across the Spectrum of Feeding | journal=Nutrients | language=en | volume=14 | issue=15 | pages=3093 | doi=10.3390/nu14153093 | doi-access=free | issn=2072-6643 | pmc=9370290 | pmid=35956275}}</ref>

Various feeding challenges can increase the risk of malnutrition in young children. These include individual factors like food [[neophobia]], temperament, and sensitivity to bitter tastes, as well as family-related factors such as education, income, food insecurity, and cultural norms. Young children tend to accept foods that are familiar and routine, as preferences are shaped through repeated exposure. Successful food acceptance requires caregivers to be patient, persistent, and willing to offer previously rejected foods multiple times. However, when caregivers label their child as "picky" or selective, they often stop offering rejected foods after just 3-5 attempts, mistakenly attributing limited food acceptance to genetics rather than learned behavior. Bribing or pressuring children to eat, along with a permissive feeding style that caters to the child's preferences, can lead to food rejection. It's common for young children to experience "food jags" (repeatedly wanting the same food) and to have shifting food preferences. While some children may exhibit a strong aversion to new foods, these reactions are usually not permanent.<ref name="reverri-2022" />

To address these challenges, providing a variety of nutrient-rich foods at every meal and snack is essential, allowing children to explore and develop their preferences. The concept of "responsive feeding", which involves a reciprocal relationship between the child and the caregiver during meals, is widely recommended. This approach is also supported by the [[Dietary Guidelines for Americans|U.S Dietary Guidelines for Americans]] and the [[Centers for Disease Control and Prevention]].<ref name="reverri-2022" />

=== Elderly nutrition ===
[[Malnutrition]] in older adults is a significant health concern, linked to increased [[Mortality rate|mortality]], [[morbidity]], and physical decline, which adversely impacts daily activities and overall quality of life. This condition is common among the elderly and can also contribute to the development of [[Geriatrics|geriatric]] syndromes.<ref name="norman-2021">{{Cite journal | last1=Norman | first1=Kristina | last2=Haß | first2=Ulrike | last3=Pirlich | first3=Matthias | date=2021-08-12 | title=Malnutrition in Older Adults—Recent Advances and Remaining Challenges | journal=Nutrients | language=en | volume=13 | issue=8 | pages=2764 | doi=10.3390/nu13082764 | doi-access=free | issn=2072-6643 | pmc=8399049 | pmid=34444924}}</ref> In older adults, malnutrition is typically indicated by unintentional weight loss or a low [[body mass index]], though hidden deficiencies, such as those involving micronutrients, are often harder to detect and frequently go unnoticed, especially in community-dwelling seniors. This is generally higher among the elderly, but has different aspects in [[Developed country|developed]] and [[undeveloped countries]].<ref name="Chwang">{{Cite journal | title=Nutrition and dietics in aged care | last=Chwang | first=Leh-Chii | journal=Nutrition and Dietics | doi=10.1111/j.1747-0080.2012.01617.x | date=September 2012 | issue=3 | volume=69 | pages=203–207}}</ref> In developed countries, the most common cause of malnutrition is [[illness]], as both [[Acute (medicine)|acute]] and [[chronic condition]]s can lead to or worsen nutritional deficits. As age increases the likelihood of disease, older adults are at the highest risk for nutritional challenges or malnutrition. The causes of malnutrition are complex and multifaceted, with aging processes further contributing to its development. The concerns faced with nutritional markers for the elderly are highlighted by the prevalence and determinants of malnutrition in adults over 65, encompassing factors from age-related changes to disease-related risks. The challenges in addressing, understanding, identifying, and treating malnutrition is key, noting that in some cases, targeted supplementation of [[Macronutrients|macro-]] and [[micronutrient]]s may be necessary when diet alone does not meet age-specific nutritional needs.<ref name="norman-2021" />

[[World Health Organization|The World Health Organization]] (WHO) has identified healthy aging as a key priority from 2016 to 2030, developing a policy framework that advocates for action across multiple sectors.<ref name="norman-2021" /> The program aims to help older adults (those aged 65 and over) maintain functional ability, ensuring their well-being and active participation in society. Older adults are the fastest-growing age group, and [[United Nations]] projections indicate that by 2050, their numbers will double those of children under five and exceed the population of adolescents aged 15 to 24. By 2050, global life expectancy, which was 72.6 years in 2019, is expected to increase by approximately five years.<ref name="norman-2021" /> Maintaining good nutritional status and adequate nutrient intake is essential for health, quality of life, and overall well-being in older age, and it plays a crucial role in healthy aging as defined by the WHO.<ref>{{Cite journal | last1=Lee | first1=Jenny Jinyoung | last2=Sultana | first2=Nargis | last3=Nishita | first3=Christy | date=2024-04-02 | title=Participant Assessment of an Alternative Flexible Congregate Nutrition Meal Program for Older Adults | journal=Journal of Nutrition in Gerontology and Geriatrics | language=en | volume=43 | issue=2 | pages=134–150 | doi=10.1080/21551197.2024.2367972 | pmid=38915295 | issn=2155-1197 | doi-access=free}}</ref>

==== Elderly Nutrition: Protein ====
While energy needs decrease with age, the demand for [[Protein (nutrient)|protein]] and certain nutrients actually rises to support normal bodily functions. Deficiencies in specific nutrients are also linked to [[cognitive decline]], a common issue among older adults. Reduced daily food intake in the elderly often leads to insufficient protein consumption, contributing to [[sarcopenia]], a condition marked by the loss of muscle mass. Approximately 30% of those aged 60 and above, and over 50% of individuals aged 80 and older, are affected by this condition. The inability to meet protein needs exacerbates health issues, including chronic muscle wasting and bone health deterioration, leading to functional decline and frailty.<ref name=":0">{{Cite journal | last1=Kaur | first1=Damanpreet | last2=Rasane | first2=Prasad | last3=Singh | first3=Jyoti | last4=Kaur | first4=Sawinder | last5=Kumar | first5=Vikas | last6=Mahato | first6=Dipendra Kumar | last7=Dey | first7=Anirban | last8=Dhawan | first8=Kajal | last9=Kumar | first9=Sudhir | date=2019-09-25 | title=Nutritional Interventions for Elderly and Considerations for the Development of Geriatric Foods | url=http://www.eurekaselect.com/172217/article | journal=Current Aging Science | language=en | volume=12 | issue=1 | pages=15–27 | doi=10.2174/1874609812666190521110548 | pmc=6971894 | pmid=31109282}}</ref> To mitigate this, older adults are advised to evenly distribute protein intake across meals—breakfast, lunch, and dinner. As aging diminishes the body's ability to synthesize muscle protein, consuming adequate [[essential amino acid]]s, especially [[leucine]], is crucial. A leucine intake of at least 3&nbsp;g per meal, achieved through 25-30g of high-quality protein, is necessary for effective muscle [[protein synthesis]].<ref name=":1">{{Cite journal | last1=Putra | first1=Christianto | last2=Konow | first2=Nicolai | last3=Gage | first3=Matthew | last4=York | first4=Catherine | last5=Mangano | first5=Kelsey | date=2021-02-26 | title=Protein Source and Muscle Health in Older Adults: A Literature Review | journal=Nutrients | language=en | volume=13 | issue=3 | pages=743 | doi=10.3390/nu13030743 | doi-access=free | issn=2072-6643 | pmc=7996767 | pmid=33652669}}</ref>

Data from the [[National Health and Nutrition Examination Survey]] III indicates that the average protein intake among the elderly is 0.9g/kg of body weight per day, with half of this intake occurring at dinner. This uneven distribution can lead to sub-optimal protein synthesis and increased use of dietary amino acids for other processes like fat storage. Therefore, evenly distributing 30&nbsp;g of protein throughout the day is recommended to enhance protein turnover and prevent muscle loss. Older adults, particularly those with [[Acute illness|acute]] or [[chronic illness]]es, may require higher protein intake, ranging from 1.2 to 1.5g/kg per day, due to a reduced [[Anabolic reaction|anabolic response]]. Some studies suggest that an intake of 1&nbsp;g/kg per day is sufficient, while others recommend 1.3 to 1.73g/kg per day for better health outcomes. Research shows that muscle mass preservation is more effectively supported by animal protein, which has a higher essential amino acid content, than by plant protein. The timing of protein intake, protein source, and amino acid content are key factors in optimizing protein absorption in the elderly.<ref name=":0" /><ref name=":1" />

==== Elderly Nutrition: Zinc ====
[[Zinc in biology|Zinc]] is a vital micronutrient that plays a crucial role in enzymatic [[catabolism]], immune cell function, [[DNA synthesis]], and various micronutrient metabolisms. In the elderly, low serum zinc levels have been reported, which weakens the immune system, making them more susceptible to infections and increasing their risk of morbidity. Aging impairs [[T cell]] function, particularly due to zinc deficiency, and the reduced synthesis of [[metallothionein]] disrupts zinc balance in the gut and other tissues.<ref name=":3">{{Cite journal | last1=Mocchegiani | first1=Eugenio | last2=Romeo | first2=Javier | last3=Malavolta | first3=Marco | last4=Costarelli | first4=Laura | last5=Giacconi | first5=Robertina | last6=Diaz | first6=Ligia-Esperanza | last7=Marcos | first7=Ascension | date=June 2013 | title=Zinc: dietary intake and impact of supplementation on immune function in elderly | journal=AGE | language=en | volume=35 | issue=3 | pages=839–860 | doi=10.1007/s11357-011-9377-3 | issn=0161-9152 | pmc=3636409 | pmid=22222917}}</ref> This deficiency is primarily due to inadequate dietary zinc intake, compounded by factors such as poor [[mastication]], oral health issues, medication use that interferes with absorption, and psychosocial factors that limit food intake. Additionally, [[Epigenetics|epigenetic]] changes like DNA [[methylation]] may impair zinc transporters, leading to decreased zinc absorption as people age. Structural changes in the gut, including altered villus shape, [[Mitochondrion|mitochondrial]] changes, crypt elongation, [[collagen]] alterations, and increased cell replication time in the crypts, also significantly affect zinc absorption in the elderly.<ref name=":0" /><ref>{{Cite journal | last=Cabrera | first=Ángel Julio Romero | date=January 2015 | title=Zinc, aging, and immunosenescence: an overview | journal=Pathobiology of Aging & Age-related Diseases | language=en | volume=5 | issue=1 | pages=25592 | doi=10.3402/pba.v5.25592 | issn=2001-0001 | pmc=4321209 | pmid=25661703}}</ref>

The recommended daily allowance of zinc is 11&nbsp;mg for older men and 8&nbsp;mg for older women, with an upper tolerable limit of 25–40&nbsp;mg per day, including both dietary and supplemental sources. However, individuals over 60 often consume less than 50% of the recommended zinc intake, which is crucial for proper body function. Data from the Third Health and Nutrition Survey in the United States revealed that only 42.5% of adults over 71 years old met adequate zinc intake levels, with many suffering from zinc deficiency. To reach the upper tolerable limit of 40&nbsp;mg per day, zinc intake from both food and supplements must be considered to help normalize serum zinc levels in deficient elderly individuals. Dietary sources such as [[seafood]], [[poultry]], [[red meat]], [[bean]]s, [[fortified cereals]], [[whole grain]]s, [[Nut (fruit)|nuts]], and [[dairy product]]s are beneficial for maintaining adequate zinc levels, though absorption is higher from animal proteins than plant-based sources.<ref name=":0" /><ref name=":3" />

==== Elderly Nutrition: Vitamin-B Complex ====
The [[Vitamin b complex|Vitamin-B complex]], which includes eight water-soluble vitamins, plays a crucial role in maintaining cellular function and preventing brain atrophy. Among the elderly, deficiencies in vitamins [[Vitamin B12|B12]], [[Vitamin B6|B6]], and [[folate]] are linked to cognitive decline and depressive symptoms.<ref name=":4">{{Cite journal | last1=Ali | first1=Mennatallah A. | last2=Hafez | first2=Hala A. | last3=Kamel | first3=Maher A. | last4=Ghamry | first4=Heba I. | last5=Shukry | first5=Mustafa | last6=Farag | first6=Mohamed A. | date=2022-09-22 | title=Dietary Vitamin B Complex: Orchestration in Human Nutrition throughout Life with Sex Differences | journal=Nutrients | language=en | volume=14 | issue=19 | pages=3940 | doi=10.3390/nu14193940 | doi-access=free | issn=2072-6643 | pmc=9573099 | pmid=36235591}}</ref>

The Recommended Dietary Allowance (RDA) for vitamin B12 is 0.9-2.4 μg/day, while the estimated average requirement in the U.S. and Canada is 0.7-2 μg/day. Elderly individuals with plasma vitamin B12 levels below 148 pmol/L are considered severely deficient, and those with levels between 148 and 221 pmol/L are marginally deficient. A deficiency in these B-vitamins, particularly B6, B12, and folate, is associated with elevated [[homocysteine]] levels, which increase the risk of [[alzheimer's disease]] and [[dementia]]. Increased intake of these vitamins can lower homocysteine levels and reduce the risk of these conditions.<ref name=":4" /> According to the [[National Health and Nutrition Examination Survey]], about 6% of elderly Americans over 70 are severely deficient in vitamin B12, and more than 20% of those over 60 are mildly deficient. This deficiency is often due to insufficient food intake and [[malabsorption]] caused by degenerative digestive conditions, as indicated by elevated plasma [[gastrin]] levels in older adults. The deficiency of vitamin B6 among institutionalized elderly in Europe ranges from below 1% to 75%. B-vitamins are primarily found in animal-based foods, making deficiencies more common among those with limited animal food intake due to cultural, religious, or economic reasons. For vegetarians, fortified foods can be a viable alternative to ensure adequate vitamin B12 levels, especially when reducing laxative use to improve absorption.<ref name=":0" />

==== Elderly Nutrition: Calcium & Vitamin D3 ====
Aging is often marked by a decline in [[bone mineral density]], leading to an increased risk of [[osteoporotic fracture]]s and reduced mobility, especially among elderly women. Women experience greater bone loss, around 2-3% per year, particularly after [[menopause]] due to [[estrogen deficiency]]. This deficiency reduces intestinal calcium absorption, decreases calcium reabsorption by the kidneys, and increases [[parathyroid hormone]] secretion, all contributing to [[bone resorption]]. Additionally, [[Vitamin d3|vitamin D3]] deficiency, common in older adults due to reduced skin synthesis and limited sun exposure, further disrupts [[Calcium in biology|calcium]] [[homeostasis]] by decreasing intestinal absorption of calcium.<ref name=":5">{{Cite journal | last1=Meehan | first1=Meghan | last2=Penckofer | first2=Sue | date=2014-07-25 | title=The Role of Vitamin D in the Aging Adult | url=http://savvysciencepublisher.com/jms/index.php/jag/article/view/245 | journal=Journal of Aging and Gerontology | volume=2 | issue=2 | pages=60–71 | doi=10.12974/2309-6128.2014.02.02.1 | issn=2309-6128 | pmc=4399494 | pmid=25893188}}</ref> As kidney function declines with age, the conversion of vitamin D3 to its active form is impaired, exacerbating the deficiency.

Serum 25(OH)D levels below 50 nmol/L are linked to muscle weakness and reduced physical function, while levels below 25-30 nmol/L increase the risk of falls and fractures. Older adults typically consume less calcium, around 600&nbsp;mg/day, which heightens their susceptibility to fractures. For optimal bone health, a calcium intake of 1000–1200&nbsp;mg/day is recommended, along with 800 IU/day of vitamin D3 for those with adequate sun exposure, and up to 2000 IU/day for those with limited sun exposure or obesity. However, dietary factors like [[phytates]], [[oxalate]]s, [[tannin]]s, and high sodium can impair calcium absorption and retention, underscoring the need to maintain sufficient levels of both calcium and vitamin D3 through diet or supplementation to reduce the risk of [[pathologic fracture]]s.<ref name=":0" /><ref name=":5" />

==== Elderly Nutrition: Iron ====
[[Iron deficiency]] is prevalent among the elderly and is a significant contributor to [[anemia]] in this population. As people age, the body's ability to balance iron storage and supply diminishes, leading to this condition. Multiple factors contribute to iron deficiency in older adults, including reduced food intake, frequent medication use, gastrointestinal malabsorption, and occult bleeding. [[Malabsorption]] can also result in excessive iron accumulation, further complicating the issue. Age-related anemia may also be linked to increased levels of [[hepcidin]], a hormone that reduces iron absorption in the intestine, leading to low iron levels.<ref name=":2">{{Cite journal | last1=Fairweather-Tait | first1=Susan J. | last2=Wawer | first2=Anna A. | last3=Gillings | first3=Rachel | last4=Jennings | first4=Amy | last5=Myint | first5=Phyo K. | date=March 2014 | title=Iron status in the elderly | journal=Mechanisms of Ageing and Development | language=en | volume=136-137 | pages=22–28 | doi=10.1016/j.mad.2013.11.005 | pmc=4157323 | pmid=24275120}}</ref>

The [[recommended daily intake]] of iron for both men and women is 8&nbsp;mg, with an upper limit of 45&nbsp;mg/day. According to the [[World Health Organization]], [[hemoglobin]] levels below 12&nbsp;g/dl in women and 13&nbsp;mg/dl in men indicate anemia.<ref name=":2" /> The [[NHANES]] III survey found that anemia affects 10.2% of women and 11% of men over 65, with prevalence increasing with age. Low iron levels not only decrease quality of life but are also associated with [[Depression (mood)|depression]], [[fatigue]], [[cognitive impairment]], and [[muscle wasting]].

Dietary components significantly influence iron absorption; tannins and [[polyphenol]]s in tea and coffee inhibit it, while [[Vitamin C]] enhances it. However, the interaction between iron and vitamin C can generate [[free radicals]], particularly in cases of [[iron overload]]. In iron deficiency, vitamin C aids absorption. [[Aspirin]] use in the elderly, often for cardiovascular disease, is linked to lower serum [[ferritin]] levels. Iron deficiency can be managed through an iron-rich diet or supplementation. Severe iron deficiency anemia may require oral iron therapy, typically with 300&nbsp;mg of [[ferrous sulfate]] containing 60&nbsp;mg of elemental iron. For those who do not respond to oral treatment, [[intravenous iron infusion]] or [[iron chelation]] for iron overload may be necessary.<ref name=":0" />

=== Clinical nutrition ===
{{Main|Clinical nutrition}}
On admission to [[intensive care unit]], energy and protein requirements are calculated to determine the targets of nutritional therapy. Enteral nutrition (administering nutrition using a [[feeding tube]]) is started within 24 to 48 hours of admission with feeding targets increased every week. The risk of aspiration (inhalation of fluid or food particles while drinking or eating) can be reduced by elevating the head, using [[prokinetic agent]], and using a [[chlorhexidine]] mouthwash. Although the presence of bowel sounds and the amount of gastric residual volume aspirated after feeding can be used to monitor the functionality of the gastrointestinal tract before feeding is started; starting nutritional therapy at this stage regardless of the functional status is feasible and safe within 36 to 48 hours of admission. [[Parenteral nutrition]] (administering of nutrition [[intravenous]]ly) should be started when enteral nutrition is not possible or sufficient or in high-risk subjects.<ref>{{Cite journal | last1=McClave | first1=Stephen A. | last2=Taylor | first2=Beth E. | last3=Martindale | first3=Robert G. | last4=Warren | first4=Malissa M. | last5=Johnson | first5=Debbie R. | last6=Braunschweig | first6=Carol | last7=McCarthy | first7=Mary S. | last8=Davanos | first8=Evangelia | last9=Rice | first9=Todd W. |last10=Cresci |first10=Gail A. | last11=Gervasio | first11=Jane M. | last12=Sacks | first12=Gordon S. | last13=Roberts | first13=Pamela R. | last14=Compher | first14=Charlene | last15=the Society of Critical Care Medicine | date=February 2016 | title=Guidelines for the Provision and Assessment of Nutrition Support Therapy in the Adult Critically Ill Patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) | journal=Journal of Parenteral and Enteral Nutrition | language=en | volume=40 | issue=2 | pages=159–211 | doi=10.1177/0148607115621863 | pmid=26773077 | s2cid=3772578 | issn=0148-6071 | doi-access=free}}</ref>

Before undergoing surgery, a subject should avoid long periods of fasting. Oral feeding should be established as soon as possible after surgery. Other aspects of nutrition such as control of glucose, reduction in risk factors that causes stress-related [[catabolism]] or impairment of gastrointestinal functions, and encourage early physical activity to encourage protein synthesis and muscle functions.<ref>{{Cite journal | last1=Weimann | first1=Arved | last2=Braga | first2=Marco | last3=Carli | first3=Franco | last4=Higashiguchi | first4=Takashi | last5=Hübner | first5=Martin | last6=Klek | first6=Stanislaw | last7=Laviano | first7=Alessandro | last8=Ljungqvist | first8=Olle | last9=Lobo | first9=Dileep N. |last10=Martindale |first10=Robert | last11=Waitzberg | first11=Dan L. | last12=Bischoff | first12=Stephan C. | last13=Singer | first13=Pierre | date=June 2017 | title=ESPEN guideline: Clinical nutrition in surgery | journal=Clinical Nutrition | language=en | volume=36 | issue=3 | pages=623–650 | doi=10.1016/j.clnu.2017.02.013 | pmid=28385477 | s2cid=4235396 | doi-access=free}}</ref>

== History of human nutrition ==
{{Main|Food history}}
Early human nutrition was largely determined by the [[availability]] and [[palatability]] of foods.<ref>Ralph M. Trüeb (23. November 2020): ''Brief History of Human Nutrition''. In: Nutrition for Healthy Hair, pp. 3–15. Springer, Cham. doi: [https://doi.org/10.1007/978-3-030-59920-1_2] {{Webarchive|url=https://web.archive.org/web/20230124005337/https://link.springer.com/chapter/10.1007/978-3-030-59920-1_2|date=2023-01-24}}</ref> Humans evolved as [[omnivore|omnivorous]] [[hunter-gatherer]]s, though the diet of humans has varied significantly depending on location and climate. The diet in the tropics tended{{when|date=January 2020}} to depend more heavily on plant foods, while the diet at higher latitudes tended more towards animal products. Analyses of postcranial and cranial remains of humans and animals from the Neolithic, along with detailed bone-modification studies, have shown that [[Human cannibalism|cannibalism]] also occurred among prehistoric humans.<ref>{{cite journal | vauthors=Villa P, Bouville C, Courtin J, Helmer D, Mahieu E, Shipman P, Belluomini G, Branca M | title=Cannibalism in the neolithic | journal=Science | volume=233 | issue=4762 | pages=431–7 | date=July 1986 | pmid=17794567 | doi=10.1126/science.233.4762.431 | bibcode=1986Sci...233..431V | s2cid=30617302}}</ref>

[[Agriculture]] developed at different times in different places, starting about 11,500 years ago, providing some cultures with a more abundant supply of [[food grain|grains]] (such as [[wheat]], [[rice]] and [[maize]]) and [[potatoes]]; and originating staples such as [[bread]], pasta [[dough]],<ref>{{cite book | last1=Guzzardi | first1=Sergio | title=Buona Pasta | url=https://books.google.com/books?id=j1YZBAAAQBAJ | publisher=Sergio Guzzardi | publication-date=2014 | page=19 | isbn=9786050314915 | access-date=21 November 2014 | quote=The first two certain dates in the history of pasta in Italy are: 1154, when in a sort of tour guide ahead of its [time] Arab geographer Al-Idrin mentions 'a food of flour in the form of wires,' called Triyah [...], which is packaged in Palermo and was exported in barrels throughout the peninsula [...]; [...] and 1279 [...]. | date=27 July 2014}}</ref> and [[tortillas]]. The [[domestication of animals]] provided some cultures with milk and dairy products.

In 2020, archeological research discovered a frescoed [[thermopolium]] (a fast-food counter) in an exceptional state of preservation from 79 in Pompeii, including 2,000-year-old foods available in some of the deep terra cotta jars.<ref>The Guardian (26 December 2020): ''[https://www.theguardian.com/world/2020/dec/26/exceptionally-well-preserved-snack-bar-unearthed-in-pompeii Exceptionally well-preserved snack bar unearthed in Pompeii] {{Webarchive|url=https://web.archive.org/web/20220926025552/https://www.theguardian.com/world/2020/dec/26/exceptionally-well-preserved-snack-bar-unearthed-in-pompeii |date=2022-09-26 }}'' (via [[Agence France-Presse]]).</ref>

=== Nutrition in antiquity ===
{{Main|Nutrition in classical antiquity}}
During [[classical antiquity]], diets consisted of simple fresh or preserved whole foods that were either locally grown or transported from neighboring areas during times of crisis.<ref>Garnsey, P. (1999). Food and society in classical antiquity (Key themes in ancient history; Key themes in ancient history). Cambridge, U.K.: Cambridge University Press.</ref><ref>Skiadas, P., & Lascaratos, J. (2001). Dietetics in ancient Greek philosophy: Plato's concepts of healthy diet. Published Online: 14 June 2001; | doi:10.1038/sj.ejcn.1601179, 55(7).</ref>

=== 18th century until today: food processing and nutrition ===
{{Main|Food processing}}
{{more citations needed|section|date=February 2019}}
Since the [[Industrial Revolution]] in the 18th and 19th century, the [[food industry|food processing industry]] has invented many [[technology|technologies]] that both help keep foods fresh longer and alter the fresh state of food as they appear in nature. [[Cooling]] and [[Frozen food|freezing]] are primary technologies used to maintain freshness, whereas many more technologies have been invented to allow foods to last longer without becoming spoiled. These latter technologies include [[pasteurisation]], [[autoclavation]], [[drying]], [[salting (food)|salting]], and separation of various components, all of which appearing to alter the original nutritional contents of food. Pasteurisation and autoclavation (heating techniques) have no doubt improved the safety of many common foods, preventing epidemics of bacterial infection.

Modern separation techniques such as [[Gristmill|milling]], [[centrifugation]], and [[Expeller pressing|pressing]] have enabled concentration of particular components of food, yielding flour, oils, juices, and so on, and even separate fatty acids, amino acids, vitamins, and minerals. Inevitably, such large-scale concentration changes the nutritional content of food, saving certain nutrients while removing others. Heating techniques may also reduce the content of many heat-labile nutrients such as certain vitamins and phytochemicals, and possibly other yet-to-be-discovered substances.<ref>{{cite journal | last=Morris | first=Audrey | author2=Audia Barnett | author3=Olive-Jean Burrows | title=Effect of Processing on Nutrient Content of Foods | journal=Cajanus | volume=37 | issue=3 | pages=160–64 | year=2004 | url=http://www.paho.org/English/CFNI/cfni-caj37No304-art-3.pdf | archive-url=https://web.archive.org/web/20070604213903/http://www.paho.org/English/CFNI/cfni-caj37No304-art-3.pdf | archive-date=2007-06-04 | url-status=live | access-date=26 October 2006}}</ref>

Because of reduced nutritional value, processed foods are often enriched or [[fortified food|fortified]] with some of the most critical nutrients (usually certain vitamins) that were lost during processing. Nonetheless, processed foods tend to have an inferior nutritional profile compared to whole, fresh foods, regarding content of both sugar and high GI starches, [[potassium]]/[[sodium]], vitamins, fiber, and of intact, unoxidized (essential) fatty acids. In addition, processed foods often contain potentially harmful substances such as oxidized fats and trans fatty acids.

A dramatic example of the effect of food processing on a population's health is the history of epidemics of [[beri-beri]] in people subsisting on polished rice. Removing the outer layer of rice by polishing it removes with it the essential vitamin [[thiamine]], causing beri-beri. Another example is the development of [[scurvy]] among infants in the late 19th century in the United States. It turned out that the vast majority of those affected were being fed milk that had been heat-treated (as suggested by [[Louis Pasteur|Pasteur]]) to control bacterial disease. Pasteurisation was effective against bacteria, but it destroyed the vitamin C.

== Research of nutrition and nutritional science ==
=== Antiquity: Start of scientific research on nutrition ===
[[File:Hippocrates pushkin02.jpg|thumb|right|upright|alt=Stone sculpture of a man's head|[[Hippocrates]] lived in about 400 BC, and Galen and the understanding of nutrition followed him for centuries.]]
Around 3000 BC the [[Vedic texts]] made mention of scientific research on nutrition.{{citation needed|date=January 2020}}{{example needed|date=January 2020}} The first{{citation needed|date=January 2020}} recorded dietary advice, carved into a [[Babylon]]ian stone tablet in about 2500 BC, cautioned those with pain inside to avoid eating [[onion]]s for three days. [[Scurvy]], later found to be a [[vitamin C deficiency]], was first described in 1500 BC in the [[Ebers Papyrus]].<ref>{{cite book | title=The Profession of Dietetics | author1=Payne-Palacio, June R. | author2=Canter, Deborah D. | year=2014 | publisher=Jones & Bartlett Learning | isbn=978-1-284-02608-5 | pages=3–4}}</ref>

According to [[Walter Gratzer]], the study of nutrition probably began during the 6th century BC. In China, the concept of ''[[qi]]'' developed, a spirit or "wind" similar to what Western Europeans later called ''[[pneuma]]''.<ref name=Gratzer40>Gratzer 2005, p. 40.</ref> Food was classified into "hot" (for example, meats, blood, ginger, and hot spices) and "cold" (green vegetables) in China, India, Malaya, and Persia.<ref name=Gratzer41 /> ''[[Humorism|Humours]]'' developed perhaps first in China alongside ''qi''.<ref name=Gratzer40 /> Ho the Physician concluded that diseases are caused by deficiencies of elements ([[Wuxing (Chinese philosophy)|Wu Xing]]: fire, water, earth, wood, and metal), and he classified diseases as well as prescribed diets.<ref name=Gratzer41>Gratzer 2005, p. 41.</ref> About the same time in Italy, [[Alcmaeon of Croton]] (a Greek) wrote of the importance of equilibrium between what goes in and what goes out, and warned that imbalance would result in disease marked by [[obesity]] or [[emaciation]].<ref name=Gratzer36>Gratzer 2005, p. 36.</ref>
[[File:Anaxagoras.png|thumb|right|Anaxagoras]]
Around 475 BC, [[Anaxagoras]] wrote that food is absorbed by the human body and, therefore, contains "homeomerics" (generative components), suggesting the existence of nutrients.<ref name=history>[https://web.archive.org/web/20060824032910/http://rcw.raiuniversity.edu/biotechnology/MScBioinformatics/generalnutrition/lecture-notes/lecture-01.pdf ''History of the Study of Nutrition in Western Culture''] (Rai University lecture notes for General Nutrition course, 2004)</ref> Around 400 BC, [[Hippocrates]], who recognized and was concerned with obesity, which may have been common in southern Europe at the time,<ref name=Gratzer36 /> said, "Let food be your medicine and medicine be your food."<ref name="Smith">{{cite journal | title=Let food by thy medicine... | author=Smith, Richard | journal=BMJ | date=24 January 2004 | volume=328 | doi=10.1136/bmj.328.7433.0-g <!-- | pages="0–g" is NOT the actual article page -- DO NOT POST--> | issue=7433 | pages=0–g–0 | pmc=318470}}</ref> The works that are still attributed to him, ''[[Hippocratic Corpus|Corpus Hippocraticum]]'', called for [[moderation]] and emphasized [[Physical exercise|exercise]].<ref name=Gratzer36 />

[[Salt#Edible salt|Salt]], [[Black pepper|pepper]] and other spices were prescribed for various ailments in various preparations for example mixed with vinegar. In the 2nd century BC, [[Cato the Elder]] believed that [[cabbage]] (or the urine of cabbage-eaters) could cure digestive diseases, ulcers, warts, and intoxication. Living about the turn of the millennium, [[Celsus|Aulus Celsus]], an ancient Roman doctor, believed in "strong" and "weak" foods (bread for example was strong, as were older animals and vegetables).<ref name=Gratzer37 />

The [[Book of Daniel]], dated to the second century BC, contains a description of a comparison in health of captured people following Jewish dietary laws versus the diet of the soldiers of the king of [[Babylon]].<ref>[http://www.biblegateway.com/passage/?search=dan#en-NIV-21743 Daniel 1:5–16] {{Webarchive|url=https://web.archive.org/web/20220714172525/https://www.biblegateway.com/passage/?search=dan#en-NIV-21743 |date=2022-07-14 }}. Biblegateway.com. Retrieved on 17 October 2011.</ref><ref>{{cite book | author=McCollum, Elmer V. | title=A History of Nutrition | publisher=The Riverside Press (Houghton Mifflin) | location=Cambridge, Mass. | year=1957 | pages=8–9}}</ref> (The story may be legendary rather than historical.)

=== 1st to 17th century ===
[[File:Galen detail.jpg|thumb|left|upright|alt=Shoulder high portrait of a man with beard and mustache wearing a cap|Followed for a millennium and a half, [[Galen]] (1st century) created the first coherent (although mistaken) theory of nutrition.<ref name=Gratzer37>Gratzer 2005, p. 37.</ref>]]

[[Galen]] was physician to gladiators in [[Pergamon]], and in [[Rome]], physician to [[Marcus Aurelius]] and the three emperors who succeeded him.<ref name=Gratzer38>Gratzer 2005, p. 38.</ref>
In use from his life in the 1st century AD until the 17th century, it was [[heresy]]{{clarify|date=January 2020}}<!-- where? in an actual religious sense?--> to disagree with the teachings of Galen for 1500 years.<ref name=Gratzer>Gratzer 2005, pp. 38, 39, 41.</ref> Most of Galen's teachings were gathered and enhanced in the late 11th century by [[Order of Saint Benedict|Benedictine monks]] at the [[Schola Medica Salernitana|School of Salerno]] in ''[[Regimen sanitatis Salernitanum]]'', which still had users in the 17th century.<ref name=Gratzer39>Gratzer 2005, p. 39.</ref> Galen believed in the bodily ''humours'' of Hippocrates, and he taught that ''pneuma'' is the source of life. [[Classical element|Four elements]] (earth, air, fire and water) combine into "complexion", which combines into states (the [[four temperaments]]: sanguine, phlegmatic, choleric, and melancholic). The states are made up of pairs of attributes (hot and moist, cold and moist, hot and dry, and cold and dry), which are made of [[humorism|four humours]]: blood, phlegm, green (or yellow) bile, and black bile (the bodily form of the elements). Galen thought that for a person to have [[gout]], [[kidney stones]], or [[arthritis]] was scandalous, which Gratzer likens to Samuel Butler's ''[[Erehwon]]'' (1872) where sickness is a crime.<ref name=Gratzer />

In the 1500s, [[Paracelsus]] was probably the first to criticize Galen publicly.<ref name=Gratzer /> Also in the 16th century, scientist and artist [[Leonardo da Vinci]] compared [[metabolism]] to a burning candle. Leonardo did not publish his works on this subject, but he was not afraid of thinking for himself and he definitely disagreed with Galen.<ref name=Gratzer41 /> Ultimately, 16th century works of [[Andreas Vesalius]], sometimes called the father of modern [[Outline of human anatomy|human anatomy]], overturned Galen's ideas.<ref>Gratzer 2005, p. 48.</ref> He was followed by piercing thought amalgamated with the era's mysticism and religion sometimes fueled by the [[mechanics]] of Newton and Galileo. [[Jan Baptist van Helmont]], who discovered several [[gas]]es such as [[carbon dioxide]], performed the first [[quantitative research|quantitative experiment]]. [[Robert Boyle]] advanced [[chemistry]]. [[Sanctorius]] measured [[body weight]]. Physician [[Herman Boerhaave]] modeled the [[digestion|digestive process]]. Physiologist [[Albrecht von Haller]] worked out the difference between [[nerve]]s and [[muscle]]s.<ref>Gratzer 2005, pp. 48–50, 52–54.</ref>

=== 18th and 19th century: Lind, Lavoisier and modern science ===
[[File:James lind.jpg|thumb|right|upright|alt=Waist high portrait drawn in pen and ink of a man balancing three books|[[James Lind]] conducted in 1747 the first controlled [[clinical trial]] in modern times, and in 1753 published ''Treatise on Scurvy''.<ref>{{cite journal | journal=Perspectives in Clinical Research | date=January–March 2010 | pages=6–10 | author=Bhatt, Arun | title=Evolution of Clinical Research: A History Before and Beyond James Lind | pmc=3149409 | pmid=21829774 | volume=1 | issue=1 | doi=10.4103/2229-3485.71839 | doi-access=free}}</ref>]]
Sometimes forgotten during his life, [[James Lind]], a physician in the British navy, performed the first [[science|scientific]] nutrition experiment in 1747. Lind discovered that [[Lime (fruit)|lime]] juice saved sailors that had been at sea for years from [[scurvy]], a deadly and painful bleeding disorder. Between 1500 and 1800, an estimated two million sailors had died of scurvy.<ref name=Willett-scurvy>{{cite book | author1=Willett, Walter C. | author2=Skerrett, Patrick J. | title=Eat, Drink, and be Healthy: The Harvard Medical School Guide To Healthy Eating | year=2005 | orig-year=2001 | isbn=978-0-684-86337-5 | publisher=Free Press (Simon & Schuster) | page=[https://archive.org/details/eatdrinkbehealth00will/page/183 183] | url-access=registration | url=https://archive.org/details/eatdrinkbehealth00will/page/183}}</ref> The discovery was ignored for forty years, but after about 1850, British sailors became known as "limeys" due to the carrying and consumption of limes aboard ship.<ref>Gratzer 2005, pp. 21–24, 32.</ref> The essential [[vitamin C]] within citrus fruits would not be identified by scientists until 1932.<ref name=Willett-scurvy />

[[File:Lavoisier humanexp.jpg|alt=Black and white engraving of Lavoisier's laboratory, man seated at left with a tube attached to his mouth, man at center conducting experiment, woman seated at right drawing, other people visible|thumb|left|By containing his assistant, [[Armand Seguin]], inside a rubber suit fitted with a tube sealed to his mouth with putty, [[Antoine Lavoisier]] first measured [[basal metabolic rate]].<ref>Gratzer 2005, p. 60.</ref> Drawing by [[Marie-Anne Pierrette Paulze|Madame Lavoisier]] (seated at right).]]
Around 1770, [[Antoine Lavoisier]] discovered the details of metabolism, demonstrating that the [[oxidation]] of food is the source of body heat. Called the most fundamental chemical discovery of the 18th century,<ref>{{cite book | author=Silberberg, Martin S. | year=2009 | title=Chemistry: The Molecular Nature of Matter and Change | publisher=McGraw-Hill | isbn=978-0-07-304859-8 | edition=5 | page=44}}</ref> Lavoisier discovered the principle of [[conservation of mass]]. His ideas made the [[phlogiston theory]] of [[combustion]] obsolete.<ref>Gratzer 2005, p. 56.</ref>

In 1790, [[George Fordyce]] recognized [[calcium]] as necessary for the survival of fowl. In the early 19th century, the elements [[carbon]], [[nitrogen]], [[hydrogen]], and [[oxygen]] were recognized{{by whom|date=November 2014}} as the primary components of food, and methods to measure their proportions were developed.<ref name="Paul Muljadi">{{cite book | url=https://books.google.com/books?id=dpNGTccTTbEC&pg=PA42 | title=Health | publisher=Paul Muljadi | author=Muljadi, Paul | pages=42}}{{dead link|date=May 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

In 1816, [[François Magendie]] discovered that dogs fed only [[carbohydrate]]s (sugar), [[fat]] (olive oil), and [[water]] died evidently of starvation, but dogs also fed protein survived&nbsp;– identifying [[protein]] as an essential dietary component.<ref>Gratzer 2005, pp. 73–74.</ref> [[William Prout]] in 1827 was the first person to divide foods into carbohydrates, fat, and protein.<ref>{{cite journal | journal=The Journal of Nutrition | title=William Prout (1785–1850): A Biographical Sketch | author=Ahrens, Richard | date=1 January 1977 | volume=107 | issue=1 | pages=17–23 | url=http://jn.nutrition.org/content/107/1/15.full.pdf+html | format=PDF | doi=10.1093/jn/107.1.15 | pmid=319206 | access-date=3 January 2020 | archive-date=17 October 2015 | archive-url=https://web.archive.org/web/20151017082420/http://jn.nutrition.org/content/107/1/15.full.pdf+html | url-status=live}}</ref> In 1840, [[Justus von Liebig]] discovered the chemical makeup of carbohydrates ([[sugar]]s), fats ([[fatty acid]]s) and proteins ([[amino acid]]s). During the 19th century, [[Jean-Baptiste Dumas]] and von Liebig quarrelled over their shared belief that animals get their protein directly from plants (animal and plant protein are the same and that humans do not create organic compounds).<ref>Gratzer 2005, p. 82.</ref> With a reputation as the leading [[organic chemistry|organic chemist]] of his day but with no credentials in [[Physiology|animal physiology]],<ref>Carpenter 1994, p. 224.</ref> von Liebig grew rich making food [[extract]]s like beef [[Liebig's Extract of Meat Company|bouillon]] and [[infant formula]] that were later found to be of questionable nutritious value.<ref>Gratzer 2005, pp. 86, 92, 95, 115.</ref>
[[File:Takaki Kanehiro.jpg|thumb|right|upright|alt=Neck high portrait of middle aged man wearing a military uniform|[[Takaki Kanehiro]] surmised that [[beriberi]] was a nutritional deficiency not an infectious disease.]]
In the early 1880s, [[Kanehiro Takaki]] observed that Japanese sailors (whose diets consisted almost entirely of white rice) developed [[beriberi]] (or endemic neuritis, a disease causing heart problems and paralysis), but British sailors and Japanese naval officers did not. Adding various types of vegetables and meats to the diets of Japanese sailors prevented the disease. (This was not because of the increased protein as Takaki supposed, but because it introduced a few parts per million of [[thiamine]] to the diet.)<ref>Carpenter 1994, p. 220.</ref>).
In the 1860s, [[Claude Bernard]] discovered that body fat can be synthesized from carbohydrate and protein, showing that the energy in blood [[glucose]] can be stored as fat or as [[glycogen]].<ref>Gratzer 2005, pp. 98–99.</ref>

In 1896, [[Eugen Baumann]] observed [[iodine]] in thyroid glands. In 1897, [[Christiaan Eijkman]] worked with natives of [[Java (island)|Java]], who also had beriberi. Eijkman observed that chickens fed the native diet of white rice developed the symptoms of beriberi but remained healthy when fed unprocessed brown rice with the outer bran intact. His assistant, [[Gerrit Grijns]] correctly identified and described the anti-beriberi substance in rice. Eijkman cured the natives by feeding them brown rice, discovering that food can cure disease. Over two decades later, nutritionists learned that the outer rice bran contains vitamin B1, also known as [[thiamine]].{{medical citation needed|date=July 2015}}

=== Early 20th century ===
[[File:Carl von Voit.jpg|thumb|left|upright|alt=Shoulder high portrait of white haired man with a mustache and beard wearing a suit and bow tie|[[Carl von Voit]] has been called the father of modern dietetics.]]
{| class="wikitable sortable" style="float:right"
|-
! Vitamin
! Isolated in...<ref>Carpenter's table gives the year each vitamin was proposed, the year isolated (shown here), the year the structure was determined, and the year that synthesis was achieved. {{cite journal | author=Carpenter, Kenneth J. | title=A Short History of Nutritional Science: Part 3 (1912–1944) | journal=The Journal of Nutrition | url=http://jn.nutrition.org/content/133/10/3023/T2.expansion.html | date=1 October 2003 | volume=133 | issue=10 | pages=3023–32 | pmid=14519779 | doi=10.1093/jn/133.10.3023 | doi-access=free | access-date=3 January 2020 | archive-date=2 November 2017 | archive-url=https://web.archive.org/web/20171102141750/http://jn.nutrition.org/content/133/10/3023/T2.expansion.html | url-status=live}} from {{cite book | author=((Combs, G.F., Jr)) | year=1992 | title=The Vitamins: Fundamental Aspects in Nutrition and Health | publisher=Academic Press | isbn=978-0-12-381980-2}}</ref>
|-
| B<sub>1</sub>: [[Thiamine|thiamin]]
| 1926
|-
|[[Vitamin C|C]]: ascorbic acid
| 1926
|-
|[[Vitamin D|D]]: calciferol
| 1931
|-
| B<sub>2</sub>: [[riboflavin]]
| 1933
|-
|[[Vitamin B6|B<sub>6</sub>]]: [[pyridoxine]], [[pyridoxal]], [[pyridoxamine]]
| 1936
|-
|[[Vitamin E|E]]: tocopherol
| 1936
|-
| B<sub>3</sub>: [[Niacin (nutrient)|niacin]]
| 1937
|-
| B<sub>8</sub>: [[biotin]]
| 1939
|-
| B<sub>9</sub>: [[folate]]
| 1939
|-
| B<sub>5</sub>: [[pantothenic acid]]
| 1939
|-
|[[Vitamin A|A]] :retinol
| 1939
|-
|[[Vitamin K|K]] :phylloquinone
| 1939
|-
|B<sub>12</sub>: [[Vitamin B12|cynocobalamin]]
|1948
|-

|}

In the early 20th century, [[Carl von Voit]] and [[Max Rubner]] independently measured [[calorie|caloric]] energy expenditure in different species of animals, applying principles of physics in nutrition. In 1906, Edith G. Willcock and [[Frederick Gowland Hopkins|Frederick Hopkins]] showed that the amino acid [[tryptophan]] aids the well-being of mice but it did not assure their growth.<ref>{{cite journal | author1=Willcock, Edith G. | author2=F. Gowland Hopkins | title=The importance of individual amino-acids in metabolism: Observations on the effect of adding tryptophane to a dietary in which zein is the sole nitrogenous constituent | journal=The Journal of Physiology | volume=35 | issue=1–2 | year=1906 | pages=88–102 | pmc=1465819 | pmid=16992872 | doi=10.1113/jphysiol.1906.sp001181}}</ref> In the middle of twelve years of attempts to isolate them,<ref>{{cite book | title=Comprehensive Biochemistry: Selected Topics in the History of Biochemistry: Personal Recollections, Part 1 | editor=Semenza, G. | year=2012 | isbn=978-0-444-59820-2 | page=117 | volume=35 | publisher=Elsevier | url=https://books.google.com/books?id=fac7AAAAQBAJ&pg=PA117 | access-date=15 March 2016 | archive-date=24 January 2023 | archive-url=https://web.archive.org/web/20230124005335/https://books.google.com/books?id=fac7AAAAQBAJ&pg=PA117 | url-status=live}}</ref> Hopkins said in a 1906 lecture that "unsuspected dietetic factors", other than calories, protein, and [[Dietary mineral|minerals]], are needed to prevent deficiency diseases.<ref>{{cite journal | title=Feeding Experiments Illustrating the Importance of Accessory Factors in Normal Dietaries | author=Hopkins, F. Gowland | journal=The Journal of Physiology | year=1912 | volume=44 | issue=5–6 | pages=425–60 | pmc=1512834 | pmid=16993143 | doi=10.1113/jphysiol.1912.sp001524}}</ref> In 1907, [[Stephen M. Babcock]] and [[Edwin B. Hart]] started the cow feeding, [[single-grain experiment]], which took nearly four years to complete.

In 1912 [[Casimir Funk]] coined the term [[vitamin]] to label a vital factor in the diet: from the words "vital" and "amine", because these unknown substances preventing scurvy, beriberi, and [[pellagra]], and were thought then to derive from ammonia. In 1913 [[Elmer McCollum]] discovered the first vitamins, fat-soluble [[vitamin A]] and water-soluble [[vitamin B]] (in 1915; later identified as a complex of several water-soluble vitamins) and named [[vitamin C]] as the then-unknown substance preventing scurvy. [[Lafayette Mendel]] (1872–1935) and [[Thomas Burr Osborne (chemist)|Thomas Osborne]] (1859–1929) also performed pioneering work on vitamins A and B.

In 1919, Sir [[Edward Mellanby]] incorrectly identified [[rickets]] as a vitamin A deficiency because he could cure it in dogs with cod liver oil.<ref name=NAS-D>{{cite web | url=http://www.nasonline.org/publications/beyond-discovery/vitamin-d.pdf | archive-url=https://web.archive.org/web/20150317071128/http://www.nasonline.org/publications/beyond-discovery/vitamin-d.pdf | archive-date=2015-03-17 | url-status=live | title=Unraveling the Enigma of Vitamin D | author1=Conlan, Roberta | author2=Elizabeth Sherman | date=October 2000 | access-date=13 June 2016 | publisher=National Academy of Sciences}}</ref> In 1922, McCollum destroyed the vitamin A in cod liver oil, but found that it still cured rickets.<ref name=NAS-D /> Also in 1922, H.M. Evans and L.S. Bishop discover [[Tocopherol|vitamin E]] as essential for rat pregnancy, originally calling it "food factor X" until 1925.

In 1925 Hart discovered that [[iron]] absorption requires trace amounts of [[copper]]. In 1927 [[Adolf Otto Reinhold Windaus]] synthesized vitamin D, for which he won the [[Nobel Prize]] in Chemistry in 1928. In 1928 [[Albert Szent-Györgyi]] isolated [[ascorbic acid]], and in 1932 proved that it is vitamin C by preventing scurvy. In 1935 he synthesized it, and in 1937 won a Nobel Prize for his efforts. Szent-Györgyi concurrently elucidated much of the [[citric acid cycle]].

In the 1930s, [[William Cumming Rose]] identified [[essential amino acid]]s, necessary protein components that the body cannot synthesize. In 1935 [[Eric Underwood]] and [[Hedley Marston]] independently discovered the necessity of [[cobalt]]. In 1936, [[Eugene Floyd DuBois]] showed that work and school performance are related to caloric intake. In 1938, [[Erhard Fernholz]] discovered the chemical structure of vitamin E.<ref name=NAS>{{cite book | author=((Subcommittee on Vitamin Tolerance, Committee on Animal Nutrition, National Research Council)) | title=Vitamin E, in Vitamin Tolerance of Animals | url=http://www.nap.edu/openbook.php?record_id=949&page=23 | year=1987 | publisher=National Academy of Sciences | access-date=22 December 2013 | doi=10.17226/949 | isbn=978-0-309-03728-0 | archive-date=24 December 2013 | archive-url=https://web.archive.org/web/20131224112924/http://www.nap.edu/openbook.php?record_id=949&page=23 | url-status=live}}</ref><ref>{{cite news | title=F.B.I. Joins Hunt for Young German Chemist | publisher=San Bernardino Daily Sun | date=18 December 1940 | url=https://www.newspapers.com/newspage/49173137/ | access-date=22 December 2013 | archive-date=24 December 2013 | archive-url=https://web.archive.org/web/20131224105303/http://www.newspapers.com/newspage/49173137/ | url-status=live}}</ref> It was synthesised the same year by [[Paul Karrer]].<ref name=NAS />

[[University of Oxford|Oxford University]] closed down its nutrition department after World War II because the subject seemed to have been completed between 1912 and 1944.<ref>{{cite journal | author=Carpenter, Kenneth J. | date=1 November 2003 | title=A Short History of Nutritional Science: Part 4 (1945–1985) | url=http://jn.nutrition.org/content/133/11/3331.long | journal=The Journal of Nutrition | volume=133 | issue=11 | pages=3331–42 | doi=10.1093/jn/133.11.3331 | pmid=14608041 | doi-access=free | access-date=3 January 2020 | archive-date=23 January 2018 | archive-url=https://web.archive.org/web/20180123220353/http://jn.nutrition.org/content/133/11/3331.long | url-status=live}}</ref>

=== Institutionalization of nutritional science in the 1950s ===
{{Main|Nutritional science}}
''Nutritional science'' as a separate, independent science discipline was institutionalized in the 1950s. At the instigation of the British physiologist [[John Yudkin]] at the [[University of London]], the degrees Bachelor of Science and Master of Science in nutritional science were established. The first students were admitted in 1953, and in 1954 the Department of Nutrition was officially opened.<ref name=Davies24July1995>Davies, Louise (24 July 1995). [https://www.independent.co.uk/news/people/obituary-john-yudkin-1593131.html "Obituary: John Yudkin"] {{Webarchive|url=https://web.archive.org/web/20191218163829/https://www.independent.co.uk/news/people/obituary-john-yudkin-1593131.html |date=2019-12-18 }}, ''The Independent''.</ref> In Germany, institutionalization followed in November 1956, when Hans-Diedrich Cremer was appointed to the chair for human nutrition in Giessen. Over time, seven other universities with similar institutions followed in Germany.<ref>Gertrud Rehner (1 June 2007): ''[http://geb.uni-giessen.de/geb/volltexte/2007/4777/pdf/SdF-2007-1_26-29.pdf 50 Jahre Institut für Ernährungswissenschaft in Gießen – Ein Rückblick] {{Webarchive|url=https://web.archive.org/web/20220314170230/http://geb.uni-giessen.de/geb/volltexte/2007/4777/pdf/SdF-2007-1_26-29.pdf |date=2022-03-14 }}''. In: Der Präsident der Justus-Liebig-Universität Gießen (Hrsg.): ''Spiegel der Forschung'', pp.&nbsp;26–30 (German only)</ref> From the 1950s to 1970s, a focus of nutritional science was on [[dietary fat]] and [[sugar]]. From the 1970s to the 1990s, attention was put on diet-related chronic diseases and [[Dietary supplement|supplementation]].<ref>{{cite journal | last1=Mozaffarian | first1=Dariush | last2=Rosenberg | first2=Irwin | last3=Uauy | first3=Ricardo | date=13 June 2018 | title=History of modern nutrition science—implications for current research, dietary guidelines, and food policy | journal=[[The BMJ]] | volume=361 | article-number=k2392 | publication-place=London | publisher=[[BMJ (company)|BMJ]] | doi=10.1136/bmj.k2392 | doi-access=free <!-- | issn=0959-8138 --> | jstor=26961096| pmid=29899124 | pmc=5998735 }}</ref>

== See also ==
{{portal|Food}}
{{div col|colwidth=20em}}

=== General ===
* [[Health]]
* [[Dieting]]
* [[Healthy diet]]

=== Substances ===
* [[Dietary supplement]]
* [[Food fortification]]
* [[Nutraceutical]]s
* [[Probiotic]]
* [[Prebiotic (nutrition)]]

=== Healthy eating advice and tools ===
* [[5 A Day]]
* [[Canada's Food Guide]]
* [[Food group]]
* [[Food guide pyramid]]
* [[Healthy eating pyramid]]
* [[MyPyramid]]
* [[Nutritional rating systems]]
* [[Nutrition scale]]

=== Types of food ===
* [[Diet food]]
* [[Fast food]]
* [[Functional food]]
* [[Junk food]]
* [[Food supplement]]
* [[Ultra-processed food]]
* [[Edible seaweed]]<ref>{{cite journal | last1=Reynolds | first1=Daman | last2=Caminiti | first2=Jeff | last3=Edmundson | first3=Scott | last4=Gao | first4=Song | last5=Wick | first5=Macdonald | last6=Huesemann | first6=Michael | title=Seaweed proteins are nutritionally valuable components in the human diet | journal=The American Journal of Clinical Nutrition | date=6 October 2022 | volume=116 | issue=4 | pages=855–861 | doi=10.1093/ajcn/nqac190 | pmid=35820048 | doi-access=free}}</ref>

=== Academic publishing ===
* ''[[Advances in Nutrition]]''
* ''[[Annual Review of Nutrition]]''
* ''[[The American Journal of Clinical Nutrition]]''

=== Biology ===
* [[Basal metabolic rate]]
* [[Bioenergetics]]
* [[Digestion]]
* [[Enzyme]]
* [[Nutrigenomics]]

=== Lists ===
* [[List of diets]]
* [[List of food additives]]
* [[List of illnesses related to poor nutrition]]
* [[List of life extension related topics]]
* [[List of macronutrients]]
* [[List of micronutrients]]
* [[List of publications in medicine#Nutrition|List of publications in nutrition]]
* [[List of unrefined sweeteners]]
* [[List of antioxidants in food|List of antioxidants]]
* [[List of phytochemicals in food|List of phytochemicals]]

=== Organizations ===
* [[Academy of Nutrition and Dietetics]]
* [[American Society for Nutrition]]
* [[British Dietetic Association]]
* [[Food and Drug Administration]]
* [[Food Fortification Initiative]]
* [[Society for Nutrition Education]]
* [[Milan Charter]]

=== Professions ===
* [[Dietitian]]
* [[Nutritionist]]
* [[Food Studies]]
{{div col end}}

== Further reading ==
* Hirschfelder, Gunther/Trummer, Manuel, [http://ieg-ego.eu/en/threads/backgrounds/food-and-drink/gunther-hirschfelder-manuel-trummer-food-and-drink?set_language=en&-C= ''Food and Drink''], [http://www.ieg-ego.eu/ EGO – European History Online], Mainz: [http://www.ieg-mainz.de/likecms/index.php Institute of European History], 2013, retrieved: 8 March 2020 ([https://d-nb.info/1044646721/34 pdf]).
* {{cite book | editor=Mahan, L.K. | editor2=Escott-Stump, S. | year=2000 | title=Krause's Food, Nutrition, and Diet Therapy | edition=10th | location=Philadelphia | publisher=W.B. Saunders Harcourt Brace | isbn=978-0-7216-7904-4}}
* {{Cite book | year=1978 | title=Human Nutrition | series=Readings from Scientific American | place=San Francisco | publisher=W.H. Freeman & Co. | isbn=978-0-7167-0183-5 | url-access=registration | url=https://archive.org/details/humannutritionre00kret}}
* {{cite book | author=Thiollet, J.-P. | title=Vitamines & minéraux | location=Paris | publisher=Anagramme | year=2001}}
* {{cite journal | vauthors=Willett WC, Stampfer MJ | title=Rebuilding the food pyramid | journal=Scientific American | volume=288 | issue=1 | pages=64–71 | date=January 2003 | pmid=12506426 | doi=10.1038/scientificamerican0103-64 | bibcode=2003SciAm.288a..64W}}

== References ==
{{Reflist|30em}}

== External links ==
{{sister project links}}
* [https://www.who.int/nutrition/topics/dietnutrition_and_chronicdiseases/en/ Diet, Nutrition and the prevention of chronic diseases] by a Joint [[WHO]]/[[FAO]] Expert consultation (2003)
* [https://web.archive.org/web/20080828021647/http://fnic.nal.usda.gov/ Food and Nutrition Information Center] of the United States Department of Agriculture
* {{usurped|1=[https://web.archive.org/web/20090118212445/http://unscn.org/ UN Standing Committee on Nutrition]}}, in English, French and Portuguese

{{Allied health professions}}
{{Public health}}
{{Diets}}

{{Authority control}}

[[Category:Applied sciences]]
[[Category:Food science]]
[[Category:Home economics]]
[[Category:Human nutrition]]
[[Category:Nutrition by type]]
[[Category:Self-care]]