For other uses of the word, see discursive. Discursive Psychology (DP) is a form of discourse analysis that focuses on psychological themes in talk, text and images.
The vitamins include vitamin D, vitamin E, vitamin A, and vitamin K, or the fat-soluble vitamins, and folate (folic acid), vitamin B12, biotin, vitamin B6, niacin, thiamin, riboflavin, pantothenic acid, and vitamin C (ascorbic acid), or the water-soluble vitamins.
Vitamins are organic compounds found in very small amounts in food and required for normal functioningâindeed, for survival. Humans are able to synthesize certain vitamins to some extent. For example, vitamin D is produced when the skin is exposed to sunlight; niacin can be synthesized from the amino acid tryptophan; and vitamin K and biotin are synthesized by bacteria living in the gut.