Scientific Names of Yeast: Saccharomyces cerevisiae (syn. S. boulardii (nom. inval.) and Candida utilis [Kingdom: Fungi; Division: Ascomycota]

Dried and powdered brewer’s yeast (active); brewer’s yeast extract
Traditional Usage:
– Acne
– Anorexia
– Antibacterial
– Appetite Loss
– Diarrhea
– Nutritive
– Mineral Deficiencies
– Traveler’s Diarrhea
– Vitamin Deficiencies

Yeasts, including Saccharomyces cerevisiae and Candida utilis [Kingdom: Fungi; Division: Ascomycota], are microscopic, one-celled fungi important for their vitamin content and for their ability to ferment carbohydrates in various substances. Yeast has been used since prehistoric times in the making of breads and wines, but their cultivation and use on an industrial scale only started after the research of Louis Pasteur in the 19th century. Yeasts, in general, are widespread in nature, occurring in the soil and on plants. Most cultivated yeasts belong to the genus Saccharomyces, literally translated as “sugar-fungus”. Today, they are also used as a source of B-complex vitamins and thiamine, as a stage in the production of various antibiotics and steroid hormones, and as feed and foodstuffs. Medicinal yeast products consist of the dried cells of Saccharomyces cerevisiae or their extracts. The German Commission E approves the use of brewer’s yeast for treating appetite loss and as a supplement for treating chronic forms of acne. The Commission E also notes antibacterial activity for Brewer’s yeast and stimulation of phagocytosis. Certain strains of it, such as Hansen CBS strain 5926, specifically bind to fibriated pathogenic bacteria that cause diarrhea thereby providing an effective treatment and prevention strategy for traveler’s diarrhea, as well as having medical applications for the treatment of acne, prevention of Candida proliferation and the alleviation of premenstrual syndrome.

Based on test tube studies, just by ingesting a small amount of viable yeast cells of fresh or lyophilized S. cerevisiae (fresh baker’s yeast), patients with congenital sucrase-isomaltase deficiency may ameliorate the malabsorption problems from the appreciable sucrase activity of yeast cells. A single report suggested that treatment with Saccharomyces cerevisiae facilitates treatment of persistent Clostridium difficile-associated infection and diarrhea. Based on animal studies, pretreatment with brewer’s yeast inhibits C. difficile toxin A-induced colonic secretion.

Active Ingredients:
Brewer’s yeast contains at least 40% protein, B complex vitamins, not less than 0.012% thiamine hydrochloride, and 0.004% for both riboflavin and folic acid and 0.025% nicotinic acid. The USDA Nutrient Database reports the following nutrient levels for dried baker’s yeast (Saccharomyces cerevisiae) per 100g (proximates): Water 7.6%; Protein 38.3%; Total lipid (fat) 4.6%; Carbohydrate, by difference 38.2% Fiber, total dietary 21%; Ash 7%; Minerals: Minerals (per 100g): Calcium, 64mg; Iron, 16.6mg; Magnesium, 98mg; Phosphorus, 1290mg; Potassium, 2000mg; Sodium, 50mg; Zinc, 6.4mg; Copper, 0.5mg; Manganese, 0.6mg; Selenium, 24.1mcg. Vitamins: Vitamin C, 0.3mg; Thiamin 2.4mg; Riboflavin 5.5 mg; Niacin 39.8mg; Pantothenic acid 11.3mg; Vitamin B-6 1.6; Folate, 2340mcg; Vitamin B-12 0.02mcg; Vitamin E 0.08mg (ate). Lipids: Fatty acids, total saturated 0.6%; Fatty acids, total monounsaturated 2.6%; Fatty acids, total polyunsaturated 0.01%; Cholesterol 0.0. Amino acids: Tryptophan 0.5g; Threonine 2.0g; Isoleucine 2.2g; Leucine 3.0g; Lysine 3.2g; Methionine 0.8g; Cystine 0.5g; Phenylalanine 1.9g; Tyrosine 1.6g; Valine 2.3g; Arginine 2.1g; Histidine 1.0g; Alanine 2.5g; Aspartic acid 3.9g; Glutamic acid 5.6g; Glycine 1.9g; Proline 1.6g; and Serine 1.9g. [Information taken from The National Agriculture Library’s USDA Nutrient Database for Standard Reference, Release 14 (July 2001)]

Suggested Amount:
For treatment of travel diarrhea: The therapeutic dosage for Hansen CBS brewer’s yeast is 250-500mg daily and continued for several days after diarrhea has ceased. For prevention of travel diarrhea: The therapeutic dosage for Hansen CBS brewer’s yeast is 250-500mg daily beginning 5 days prior to traveling and continued for several days after traveling. For acne: The therapeutic dosage for Hansen CBS brewer’s yeast is 750mg daily.

Drug Interactions:
Brewer’s yeast taken together with MAO-inhibitors may cause an interaction leading to increased blood pressure and therefore simultaneous use is not recommended. The use of it together with drugs for eliminating fungi can affect the activity and effectiveness of brewer’s yeast.

Brewer’s yeast as a drug is contraindicated in children below 2 years of age and is not recommended for small children. Brewer’s yeast is also contraindicated in cases of yeast allergy. Brewer’s yeast taken together with MAO-inhibitors may cause an interaction leading to increased blood pressure and therefore simultaneous use is not recommended. Caution is also advised in the clinical use of Saccharomyces boulardii (nom. inval.) in immuno-compromised patients until further study is undertaken.

Side Effects:
Ingestion of yeast in therapeutic quantities may cause flatulence. Yeast intolerance may also occur in susceptible persons, indicated by itching, rash and other common signs of allergy.


Blumenthal M, Goldberg A, Brinckmann J 2000. Herbal Medicine: Expanded Commission E Monographs. Copyright American Botanical Council. Publ. by Integrative Medicine Communications, 1029 Chestnut Street, Newton, MA 02464. Pp. 424-428.

Izadnia F, Wong CT, Kocoshis SA. 1998. Brewer’s yeast and Saccharomyces boulardii both attenuate Clostridium difficile-induced colonic secretion in the rat. Dig Dis Sci. 1998 Sep; 43(9): 2055-60.

Treem WR. 1996. Clinical heterogeneity in congenital sucrase-isomaltase deficiency. J Pediatr. 1996 Jun; 128(6): 727-9.

Harms HK, Bertele-Harms RM, Bruer-Kleis D. 1987. Enzyme-substitution therapy with Saccharomyces cerevisiae in congenital sucrase-isomaltase deficiency. N Engl J Med. 1987 May 21; 316(21): 1306-9.

Zoppi G, Balsamo V, Deganello A, Iacono G, Saccomani F, Benoni G. 1982. Oral bacteriotherapy in clinical practice. II. The use of different preparations in the treatment of acute diarrhoea. Eur J Pediatr. 1982 Sep; 139(1): 22-4.