Brewer's yeast is derived from the unicellular fungus, which causes the fermentation process basic to the brewing of beer.Dried brewer's yeast is a rich source of several nutrients,including the B vitamins thiamin,riboflavin,niacin,pyridoxine,pantothenic acid,folate,vitamin B12 and biotin,and such trace minerals as chromium and selenium.It also contains beta-glucans,ribonucleic acid or RNA,para-aminobenzoic acid and myo-inositol.Brewer's yeast has been a popular nutritional supplement for many years.Much of the brewer's yeast marketed for nutritional nutritional supplement use is grown specifically for that markteplace.The supplements are prepared from dry,crushed cells.The cells are not alive