Editing Nutrient (section)

====Vitamins and vitamers====
{{Main|Vitamin}}
Vitamins occur in a variety of related forms known as [[vitamers]]. The vitamers of a given vitamin perform the functions of that vitamin and prevent symptoms of deficiency of that vitamin. Vitamins are those essential organic molecules that are not classified as amino acids or fatty acids. They commonly function as [[enzymatic cofactor]]s, metabolic regulators or [[antioxidant]]s. Humans require thirteen vitamins in their diet, most of which are actually groups of related molecules (e.g. [[vitamin E]] includes [[tocopherol]]s and [[tocotrienol]]s):<ref>{{cite journal | vauthors = Brigelius-Flohé R, Traber MG | title = Vitamin E: function and metabolism | journal = FASEB Journal | volume = 13 | issue = 10 | pages = 1145–55 | date = July 1999 | pmid = 10385606 | doi = 10.1096/fasebj.13.10.1145 | s2cid = 7031925 | doi-access = free }}</ref> vitamins A, C, D, E, K, [[thiamine]] (B<sub>1</sub>), [[riboflavin]] (B<sub>2</sub>), [[Niacin (nutrient)|niacin]] (B<sub>3</sub>), [[pantothenic acid]] (B<sub>5</sub>), [[pyridoxine]] (B<sub>6</sub>), [[biotin]] (B<sub>7</sub>), [[folate]] (B<sub>9</sub>), and [[cobalamin]] (B<sub>12</sub>). The requirement for vitamin D is conditional, as people who get sufficient exposure to ultraviolet light, either from the sun or an artificial source, synthesize vitamin D in the skin.<ref name="lpi">{{cite web |title=Vitamin D |url=https://lpi.oregonstate.edu/mic/vitamins/vitamin-D |publisher=Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis |access-date=14 March 2022 |date=11 February 2021}}</ref>