Now Brewers Yeast Super Food Nutritional Yeast Made From the Single-celled Organism Saccharomyces Cerevisiae, Commonly Known as Brewer's Yeast. It is a Rich Source of Protein, B Vitamins, Minerals, and Other Nutrients, and Can Be Used as a Dietary Supplement or as a Flavor Enhancer in Cooking. It is Often Favored by Vegans and Vegetarians as a Natural Source of Vitamin B12.