Vitamins are organic compounds found in foods that are necessary in human and animal diets to sustain life and health. There are thirteen vitamins that have been identified as necessary for human health, and several other vitamin-like substances also contribute to good nutrition. The vitamins are named by letters--vitamin A, vitamin C, D, E, K, and eight B vitamins. Because the B vitamins were originally thought to be one vitamin, they were first differentiated by numeral subscripts. Currently B₆ and B₁₂ retain the numeric names, and the rest of the B group vitamins are thiamine, riboflavin, niacin, pantothenic acid, biotin, and folic acid.

The discovery of vitamins was a patchwork affair, taking many scientists in distant communities years to piece together the story of the vitaminsÕ role in nutrition. Many of the discoveries of vitamins came from doctors working on the cure of diseases such as rickets, scurvy...