A type of baker's yeast where it contains dehydrated yeast cells of a particular strain of Saccharomyces cerevisiae (which may be mixed with starchy material). It is a commercially-available by-product from the brewing industry as a natural source of protein and vitamin B complex.
Possible sources include: brewers dried yeast, debittered brewers dried yeast, or primary dried yeast. Its components are 45% of protein, in 1 g not less than 0.3 mg of nicotinic acid, 0.04 mg riboflavin, and 0.12 mg thiamin hydrochloride. Since it contains vitamin B complex it is sometimes used as a dietary supplement.