Editing Vitamin A (section)

==Dietary recommendations==
The US [[National Academy of Medicine]] updated [[Dietary Reference Intake]]s (DRIs) in 2001 for vitamin A, which included Recommended Dietary Allowances (RDAs).<ref name="DRI VitA"/> For infants up to 12 months, there was not sufficient information to establish an RDA, so Adequate Intake (AI) is shown instead. As for safety, [[tolerable upper intake level]]s (ULs) were also established. For ULs, carotenoids are not added when calculating total vitamin A intake for safety assessments.<ref name="DRI VitA"/>

{| class="wikitable"
|-
! colspan=2 | Life stage group
! US RDAs or AIs<br /> (μg RAE/day)<ref name="DRI VitA"/>
! US Upper limits<br /> (μg/day)<ref name="DRI VitA"/>
|-
| rowspan=2 | '''Infants'''
| 0–6 months || 400 (AI) || 600
|-
| 7–12 months || 500 (AI) || 600
|-
| rowspan=2 | '''Children'''
| 1–3 years || 300 || 600
|-
| 4–8 years || 400 || 900
|-
| rowspan=3 | '''Males'''
| 9–13 years || 600 || 1700
|-
| 14–18 years || 900 || 2800
|-
| >19<!-- – >70--> years || 900 || 3000
|-
| rowspan=3 | '''Females'''
| 9–13 years || 600 || 1700
|-
| 14–18 years || 700 || 2800
|-
| >19<!--– >70--> years || 700 || 3000
|-
| rowspan=2 | '''Pregnancy'''
| <19 years || 750 || 2800
|-
| >19<!-- – >50--> years || 770 || 3000
|-
| rowspan=2 | '''Lactation'''
| <19 years || 1200 || 2800
|-
| >19<!-- – >50--> years || 1300 || 3000
|}

The [[European Food Safety Authority]] (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL are defined the same as in the United States. For women and men of ages 15 and older, the PRIs are set respectively at 650 and 750 μg&nbsp;RE/day. PRI for pregnancy is 700 μg&nbsp;RE/day, for lactation 1300/day. For children of ages 1–14 years, the PRIs increase with age from 250 to 600 μg&nbsp;RE/day. These PRIs are similar to the US RDAs.<ref>{{cite web |title=Overview on Dietary Reference Values for the EU population as derived by the EFSA Panel on Dietetic Products, Nutrition and Allergies |year=2017 |url=https://www.efsa.europa.eu/sites/default/files/assets/DRV_Summary_tables_jan_17.pdf |publisher=European Food Safety Authority (EFSA) |access-date=4 September 2017 |archive-date=28 August 2017 |archive-url=https://web.archive.org/web/20170828082247/https://www.efsa.europa.eu/sites/default/files/assets/DRV_Summary_tables_jan_17.pdf |url-status=live }}</ref> The EFSA reviewed the same safety question as the United States, and set ULs at 800 for ages 1–3, 1100 for ages 4–6, 1500 for ages 7–10, 2000 for ages 11–14, 2600 for ages 15–17 and 3000 μg/day for ages 18 and older for preformed vitamin A, i.e., not including dietary contributions from carotenoids.<ref name=EFSA-UL>{{cite web |title=Tolerable Upper Intake Levels For Vitamins And Minerals |publisher=European Food Safety Authority |year=2006 |url=http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf |access-date=4 September 2017 |archive-date=19 September 2017 |archive-url=https://web.archive.org/web/20170919040144/http://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf |url-status=live }}</ref>

===Safety===
Vitamin A toxicity ([[hypervitaminosis A]]) occurs when too much vitamin A accumulates in the body. It comes from consumption of preformed vitamin A but not of carotenoids, as conversion of the latter to retinol is suppressed by the presence of adequate retinol.

====Retinol safety====
{{Main|Hypervitaminosis A}}

There are historical reports of acute hypervitaminosis from Arctic explorers consuming bearded seal or polar bear liver, both very rich sources of stored retinol,<ref>{{cite journal | vauthors = Rodahl K, Moore T | title = The vitamin A content and toxicity of bear and seal liver | journal = The Biochemical Journal | volume = 37 | issue = 2 | pages = 166–168 | date = July 1943 | pmid = 16747610 | pmc = 1257872 | doi = 10.1042/bj0370166 }}</ref> and there are also case reports of acute hypervitaminosis from consuming fish liver,<ref>{{cite journal | vauthors = Schmitt C, Domangé B, Torrents R, de Haro L, Simon N | title = Hypervitaminosis A Following the Ingestion of Fish Liver: Report on 3 Cases from the Poison Control Center in Marseille | journal = Wilderness & Environmental Medicine | volume = 31 | issue = 4 | pages = 454–456 | date = December 2020 | pmid = 32861618 | doi = 10.1016/j.wem.2020.06.003 | s2cid = 221384282 | doi-access = free | title-link = doi }}</ref> but otherwise there is no risk from consuming too much via commonly consumed foods. Only consumption of retinol-containing dietary supplements can result in acute or chronic toxicity.<ref name=PKIN2020VitA/> Acute toxicity occurs after a single or short-term doses of greater than 150,000 μg. Symptoms include blurred vision, nausea, vomiting, dizziness and headache within 8 to 24 hours. For infants ages 0–6 months given an oral dose to prevent development of vitamin A deficiency, bulging skull fontanel was evident after 24 hours, usually resolved by 72 hours.<ref name="Imdad2016">{{cite journal | vauthors = Imdad A, Ahmed Z, Bhutta ZA | title = Vitamin A supplementation for the prevention of morbidity and mortality in infants one to six months of age | journal = The Cochrane Database of Systematic Reviews | volume = 9 | issue = 9 | pages = CD007480 | date = September 2016 | pmid = 27681486 | pmc = 6457829 | doi = 10.1002/14651858.CD007480.pub3 }}</ref> Chronic toxicity may occur with long-term consumption of vitamin A at doses of 25,000–33,000 IU/day for several months.<ref name=lpi/> Excessive consumption of alcohol can lead to chronic toxicity at lower intakes.<ref name=ods/> Symptoms may include nervous system effects, liver abnormalities, [[fatigue]], muscle weakness, bone and skin changes and others. The adverse effects of both acute and chronic toxicity are reversed after consumption is stopped.<ref name="DRI VitA"/>

In 2001, for the purpose of determining ULs for adults, the US Institute of Medicine considered three primary adverse effects and settled on two: [[teratogen]]icity, i.e., causing birth defects, and liver abnormalities. Reduced bone mineral density was considered, but dismissed because the human evidence was contradictory.<ref name="DRI VitA"/> During pregnancy, especially during the first trimester, consumption of retinol in amounts exceeding 4,500 μg/day increased the risk of birth defects, but not below that amount, thus setting a "No-Observed Adverse-Effect Level" (NOAEL).{{Medical citation needed|date=December 2024}} Given the quality of the clinical trial evidence, the NOAEL was divided by an uncertainty factor of 1.5 to set the UL for women of reproductive age at 3,000 μg/day of preformed vitamin A.{{Medical citation needed|date=December 2024}} For all other adults, liver abnormalities were detected at intakes above 14,000 μg/day.{{Medical citation needed|date=December 2024}} Given the weak quality of the clinical evidence, an uncertainty factor of 5 was used, and with rounding, the UL was set at 3,000 μg/day.{{Citation needed|date=December 2024}}

For children, ULs were extrapolated from the adult value, adjusted for relative body weight. For infants, several case studies reported adverse effects that include bulging fontanels, increased intracranial pressure, loss of appetite, hyperirritability and skin peeling after chronic ingestion of the order of 6,000 or more μg/day. Given the small database, an uncertainty factor of 10 divided into the "Lowest-Observed-Adverse-Effect Level" (LOAEL) led to a UL of 600 μg/day.<ref name="DRI VitA"/>

====β-carotene safety====
No adverse effects other than [[carotenemia]] have been reported for consumption of β-carotene rich foods. Supplementation with β-carotene does not cause hypervitaminosis A.<ref name=PKIN2020Carotenoids/> Two large clinical trials (ATBC and CARET) were conducted in tobacco smokers to see if years of β-carotene supplementation at 20 or 30&nbsp;mg/day in oil-filled capsules would reduce the risk of lung cancer.<ref name="DRItextBetaCarotene"/> These trials were implemented because observational studies had reported a lower incidence of lung cancer in tobacco smokers who had diets higher in β-carotene. Unexpectedly, high-dose β-carotene or retinol supplementation resulted in a higher incidence of lung cancer and of total mortality due to cardiac mortality.<ref>{{Cite journal |date=14 April 1994 |title=The Effect of Vitamin E and Beta Carotene on the Incidence of Lung Cancer and Other Cancers in Male Smokers |url=http://www.nejm.org/doi/abs/10.1056/NEJM199404143301501 |journal=New England Journal of Medicine |language=en |volume=330 |issue=15 |pages=1029–1035 |doi=10.1056/NEJM199404143301501 |pmid=8127329 |issn=0028-4793 | vauthors = Alpha-Tocopherol BC }}</ref><ref name=PKIN2020Carotenoids/> Taking this and other evidence into consideration, the U.S. Institute of Medicine decided not to set a Tolerable Upper Intake Level (UL) for β-carotene.<ref name=PKIN2020Carotenoids/><ref name="DRItextBetaCarotene">{{cite book |title=Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids |chapter=Beta-carotene and other Carotenoids |publisher=The National Academies Press |year=2000 |location=Washington, DC |pages=325–382 |doi=10.17226/9810 |pmid=25077263 |chapter-url=https://www.nap.edu/read/9810/chapter/10 |access-date=19 December 2021 |isbn=978-0-309-06935-9 |url-status=live |archive-url=https://web.archive.org/web/20170902180153/https://www.nap.edu/read/9810/chapter/10 |archive-date=2 September 2017|author1=Institute of Medicine (US) Panel on Dietary Antioxidants Related Compounds }}</ref> The European Food Safety Authority, acting for the European Union, also decided not to set a UL for β-carotene.<ref name=EFSA-UL/>
[[File:Carrots.JPG|thumb|upright|right|250px|[[Carrot]]s are a rich source of β-carotene.]]

====Carotenosis====
[[Carotenosis|Carotenoderma]], also referred to as carotenemia, is a benign and reversible medical condition where an excess of dietary carotenoids results in orange discoloration of the outermost skin layer. It is associated with a high blood β-carotene value. This can occur after a month or two of consumption of β-carotene rich foods, such as carrots, carrot juice, tangerine juice, mangos, or in Africa, red palm oil. β-carotene dietary supplements can have the same effect. The discoloration extends to palms and soles of feet, but not to the [[sclera|white of the eye]], which helps distinguish the condition from [[jaundice]].<ref>{{cite journal | vauthors = Maharshak N, Shapiro J, Trau H | title = Carotenoderma – a review of the current literature | journal = International Journal of Dermatology | volume = 42 | issue = 3 | pages = 178–181 | date = March 2003 | pmid = 12653910 | doi = 10.1046/j.1365-4362.2003.01657.x | s2cid = 27934066 | doi-access = free | title-link = doi }}</ref> Consumption of greater than 30&nbsp;mg/day for a prolonged period has been confirmed as leading to carotenemia.<ref name=PKIN2020Carotenoids/><ref>{{cite book | vauthors = Al Nasser Y, Jamal Z, Albugeaey M | chapter = Carotenemia | title = StatPearls | location = Treasure Island (FL) | publisher = StatPearls Publishing | date = 2021 | pmid = 30521299 | doi = 10.1007/s00253-001-0902-7 | s2cid = 22232461 }}</ref>

===U.S. labeling===
For U.S. food and dietary supplement labeling purposes, the amount in a serving is expressed as a percent of Daily Value (%DV). For vitamin A labeling purposes, 100% of the Daily Value was set at 5,000 IU, but it was revised to 900 μg RAE on 27 May 2016.<ref name="FedReg">{{cite web |url=https://www.gpo.gov/fdsys/pkg/FR-2016-05-27/pdf/2016-11867.pdf |title=Federal Register May 27, 2016 Food Labeling: Revision of the Nutrition and Supplement Facts Labels |access-date=4 September 2017 |archive-date=8 August 2016 |archive-url=https://web.archive.org/web/20160808164651/https://www.gpo.gov/fdsys/pkg/FR-2016-05-27/pdf/2016-11867.pdf |url-status=live }}</ref><ref>{{cite web | title=Daily Value Reference of the Dietary Supplement Label Database (DSLD) | website=Dietary Supplement Label Database (DSLD) | url=https://www.dsld.nlm.nih.gov/dsld/dailyvalue.jsp | access-date=18 December 2021 | archive-date=7 April 2020 | archive-url=https://web.archive.org/web/20200407073956/https://dsld.nlm.nih.gov/dsld/dailyvalue.jsp | url-status=dead }}</ref> A table of the old and new adult daily values is provided at [[Reference Daily Intake]].