|See Also||Food Supplements|
Brewer's yeast comes from the single-celled fungus, Saccharomyces cerevisiae; it causes the fermentation process used in the brewing of beer. It is a rich source of many nutrients such as thiamin, riboflavin, niacin, pyridoxine, pantothenic acid, folate, vitamin B12, biotin, chromium, and selenium. It also contains beta-glucans, ribonucleic acid (RNA), para aminobenzoic acid, and myo-inositol. Supplementation with brewer's yeast provides all of these nutrients. Brewer's yeast with high selenium content has anticarcinogenic activity whereas brewer's yeast with high chromium has antidiabetic activity. The Saccaromyces cerevisiae used in marketed supplements is dried and crushed and is no longer alive 
The following foods have the highest concentration of brewer's yeast:
- some breads
- soy sauce
The following are the primary uses for brewer's yeast: 
- Cancer Prevention: Selenium-enriched brewer's yeast was found in one study to reduce the incidence of lung cancer, colorectal cancer, prostate cancer, total cancer, and total cancer mortality.
- Type II Diabetes: High-chromium brewer's yeast has been found in some studies to improve glucose tolerance in type II diabetics. More studies are needed in this area as the results have been mixed.
- Other: may reduce blood cholesterol levels, may treat contact dermatitis, may increase energy, may treat diarrhea, acne, furunculosis, colds, cough, dyspepsia, inflammatory conditions, and various infections (less support is available for these indications)
The recommended dosages have not yet been established. To determine what your specific requirements are talk to your naturopathic doctor or other trained medical professional.
- Brewer's yeast is available in powder and flake form and can be added to cooking in order to increase the nutritional value. It also comes in capsule and tablet form 
Brewer's Yeast is generally well tolerated.
- Pregnancy and Breastfeeding
- Long-term safety has not been established and therefore supplementation form is best avoided when pregnant or breastfeeding.
- Individuals with hypersensitivity to any components of brewer's yeast and in those with intestinal disease. Individuals that are allergic to brewer's yeast may develop flatulence, diarrhea or nausea.
- Drug Interactions: 
- Hendler Sheldon S, Rorvik David (Editors) (2001) PDR for Nutritional Supplements, Medical Economics Company Inc.