Editing Antioxidant (section)

=== Relation to diet ===

The dietary antioxidant [[vitamin]]s A, C, and E are essential and required in [[Dietary Reference Intake|specific daily amounts]] to prevent diseases.<ref name="nih" /><ref name="Stanner">{{Cite journal |vauthors=Stanner SA, Hughes J, Kelly CN, Buttriss J |date=May 2004 |title=A review of the epidemiological evidence for the 'antioxidant hypothesis' |journal=Public Health Nutrition |volume=7 |issue=3 |pages=407–22 |doi=10.1079/PHN2003543 |pmid=15153272 |doi-access=free}}</ref><ref>''[http://www.dietandcancerreport.org/?p=ER Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective] {{Webarchive|url=https://web.archive.org/web/20150923214620/http://www.dietandcancerreport.org/?p=ER|date=23 September 2015}}''. [[World Cancer Research Fund]] (2007). {{ISBN|978-0-9722522-2-5}}.</ref> [[Polyphenol]]s, which have antioxidant properties [[in vitro]] due to their free [[hydroxy group]]s,<ref>{{Cite journal |last1=Rice-Evans |first1=Catherine A. |last2=Miller |first2=Nicholas J. |last3=Paganga |first3=George |date=1996 |title=Structure-antioxidant activity relationships of flavonoids and phenolic acids |url=https://linkinghub.elsevier.com/retrieve/pii/0891584995022279 |journal=Free Radical Biology and Medicine |language=en |volume=20 |issue=7 |pages=933–956 |doi=10.1016/0891-5849(95)02227-9 |pmid=8743980}}</ref> are extensively metabolized by [[catechol-O-methyltransferase]] which methylates free hydroxyl groups, and thereby prevents them from acting as antioxidants in vivo.<ref>{{Cite journal |vauthors=Del Rio D, Rodriguez-Mateos A, Spencer JP, Tognolini M, Borges G, Crozier A |date=May 2013 |title=Dietary (poly)phenolics in human health: structures, bioavailability, and evidence of protective effects against chronic diseases |journal=Antioxidants & Redox Signaling |volume=18 |issue=14 |pages=1818–1892 |doi=10.1089/ars.2012.4581 |pmc=3619154 |pmid=22794138}}</ref><ref name="lpi">{{Cite web |date=2016 |title=Flavonoids |url=http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/flavonoids |access-date=24 July 2016 |publisher=Linus Pauling Institute, Oregon State University, Corvallis}}</ref>