Editing Flatulence (section)

==Cause==
Intestinal gas is composed of varying quantities of exogenous sources and endogenous sources.<ref name="NIH Gas in the">{{cite web |url=http://www.niddk.nih.gov/health-information/health-topics/digestive-diseases/gas/Pages/facts.aspx |title=Gas in the Digestive Tract |publisher=[[National Institute of Diabetes and Digestive and Kidney Diseases]] |access-date=August 24, 2015 |archive-date=August 13, 2015 |archive-url=https://web.archive.org/web/20150813012551/http://www.niddk.nih.gov/health-information/health-topics/digestive-diseases/gas/Pages/facts.aspx |url-status=dead }}</ref> The exogenous gases are swallowed ([[aerophagia]]) when eating or drinking or increased swallowing during times of excessive salivation (as might occur when nauseated or as the result of [[gastroesophageal reflux]] disease). The [[endogenous]] gases are produced either as a by-product of digesting certain types of food, or of incomplete [[digestion]], as is the case during [[steatorrhea]]. Anything that causes food to be incompletely digested by the [[stomach]] or [[small intestine]] may cause flatulence when the material arrives in the large intestine, due to [[Fermentation (biochemistry)|fermentation]] by [[yeast]] or [[prokaryotes]] normally or abnormally present in the [[Human gastrointestinal tract|gastrointestinal tract]].

Flatulence-producing foods are typically high in certain [[polysaccharide]]s, especially [[oligosaccharides]] such as [[inulin]]. Those foods include [[bean]]s, [[lentil]]s, [[dairy product]]s, [[onion]]s, [[garlic]], [[scallion|spring onions]], [[leek]]s, [[turnip]]s, [[rutabaga|swedes]], [[radish]]es, [[sweet potato]]es, [[potatoes]], [[cashew]]s, [[Jerusalem artichoke]]s, [[oat]]s, [[wheat]], and [[yeast]] in [[bread]]s. [[Cauliflower]], [[broccoli]], [[cabbage]], [[Brussels sprouts]] and other [[cruciferous vegetables]] that belong to the genus ''[[Brassica]]'' are commonly reputed to not only increase flatulence, but to increase the pungency of the flatus.<ref>{{cite news|url=https://www.medicalnewstoday.com/articles/7622.php|title=Flatulence: Causes, remedies, and complications|work=Medical News Today|access-date=2018-04-17}}</ref><ref>{{cite news|url=https://paleoleap.com/eat-brassicas-just-ones-know/|title=Paleo Foods: Brassicas (and not Just the Ones you Know) {{!}} Paleo Leap|date=2014-09-14|work=Paleo Leap {{!}} Paleo diet Recipes & Tips|access-date=2018-04-17}}</ref>

In beans, endogenous gases seem to arise from complex oligosaccharides ([[carbohydrate]]s) that are particularly resistant to digestion by mammals, but are readily digestible by [[microorganisms]] ([[methanogenesis|methane-producing]] archaea; ''[[Methanobrevibacter smithii]]'') that inhabit the [[digestive tract]]. These oligosaccharides pass through the small intestine largely unchanged, and when they reach the large intestine, [[bacteria]] ferment them, producing copious amounts of flatus.<ref name="McGee">{{cite book| last=McGee| first=Harold |author-link=Harold McGee |title=On Food and Cooking| publisher=[[Charles Scribner's Sons|Scribner]] | year=1984| isbn=0-684-84328-5| pages=257–58| title-link=On Food and Cooking }}</ref>

When excessive or malodorous, flatus can be a sign of a health disorder, such as [[irritable bowel syndrome]], [[celiac disease]], [[non-celiac gluten sensitivity]] or [[lactose intolerance]]. It can also be caused by certain medicines, such as [[ibuprofen]], [[laxative]]s, [[antifungal]] medicines or [[statin]]s.<ref name=NHS2017 /><ref name=CzajaBulsa2015>{{cite journal |author=Czaja-Bulsa G |title=Non coeliac gluten sensitivity – A new disease with gluten intolerance |journal=Clin Nutr|volume=34|issue=2|pages=189–94|date=Apr 2015|pmid=25245857 |doi=10.1016/j.clnu.2014.08.012|type=Review|doi-access=free}}</ref> Some infections, such as [[giardiasis]], are also associated with flatulence.<ref>{{cite journal|pmc=2272232 | pmid=1499664 | volume=109 | issue=1 | title=Giardia – diagnosis, clinical course and epidemiology: A review |date= 1992|jstor=3863897 | author=Flanagan PA | journal=[[Epidemiology and Infection]] | pages=1–22}}</ref>

Interest in the causes of flatulence was spurred by high-altitude [[flight]] and [[human spaceflight]]; the low [[atmospheric pressure]], confined conditions, and stresses peculiar to those endeavours were cause for concern.<ref name="McGee"/> In the field of mountaineering, the phenomenon of [[high altitude flatus expulsion]] was first recorded over two hundred years ago.