A group of water-soluble vitamins that characteristically serve as components of coenzymes . Plants and many microorganisms can manufacture B vitamins but dietary sources are essential for most animals. Heat and light tend to destroy B vitamins.
Deficiency leads to beriberi in humans and to polyneuritis in birds.
Good sources include brewer's yeast, wheatgerm, beans, peas, and green vegetables. It is a constituent of the coenzymes FAD and FMN, which have an important role in the metabolism of all major nutrients as well as in the oxidative phosphorylation reactions of the electron transport chain . Deficiency of B 2 causes inflammation of the tongue and lips and mouth sores. Deficiency causes retarded growth, dermatitis, convulsions, and other symptoms. Liver is especially rich in it.