Yeast is a broad classification of microbial fungi sometimes used in food preparation and human nutrition. The yeast known as Saccharomyces cerevisiae, or brewer's yeast, is frequently used as a B-vitamin supplement for people following a strict vegan diet. It provides a spectrum of nutritional compounds and has a reputation for facilitating weight gain.
Brewer's yeast supplements consist of S. cerevisiae, a single-celled fungus. The yeast is deactivated, or no longer capable of reproduction, when used in nutritional supplements and food. S. cerevisiae is also used directly in the manufacture of nutritional yeast and yeast extract. Brewer's yeast owes its common name to its extensive use in the fermentation and production of beer. It is also known as ale yeast, budding yeast and top-fermenting yeast. Although other fungi might also be used in beer production, S. cerevisiae is the only form of beer-making yeast commonly sold as a nutritional supplement.
Weight Gain Claims
Brewer's yeast has a reputation as a nutritional supplement that facilitates weight gain. Athletes interested in bodybuilding have used it for this purpose, as have people recovering from chemotherapy and eating disorders. The University of Maryland Medical Center acknowledges that brewer's yeast contains many healthy micronutrients, such as vitamins and minerals. It is also a potent source of protein; the brewer's yeast supplement manufactured by Solgar contains 14 grams of protein in each 2 tbsp. serving.
Lack of Evidence
According to the University of Maryland Medical Center, no solid scientific evidence suggests that brewer's yeast appreciably increases a person's weight. With only 100 calories per 2 tbsp., brewer's yeast is not particularly high in calories. Limited evidence also suggests that chromium, a mineral found in brewer's yeast, actually leads to weight loss. Although brewer's yeast might help provide essential nutrients necessary for energy and overall health, no scientific evidence demonstrates it enables weight gain.
Brewer's yeast supplements offer significant health benefits beyond their theoretical ability to enable weight gain. Vegans are known to use brewer's yeast as a natural, animal-free source of B-vitamins, including thiamine, riboflavin, niacin, pantothenic acid, pyridoxine, folic acid and biotin, which might be lacking in a diet containing no animal products. Brewer's yeast is also an excellent source of the trace minerals chromium and selenium, which are necessary for human health. Consult your primary health care provider before using brewer's yeast to self-treat any medical condition, including perceived vitamin deficiency.