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Brewer's yeast

Medically reviewed on Apr 12, 2018

Scientific Name(s): Saccharomyces cerevisiae

Common Name(s): Yeast , Baker's yeast , Brewer's yeast , dried yeast fermentate , EpiCor , Fibercel , Betafectin


Brewer's yeast is traditionally used as a source of vitamin B, selenium, and chromium, especially by vegetarians. Clinical trials have evaluated yeast for a role in immunomodulation, respiratory infections, prevention of postsurgical infections (as beta-glucan), and as a source of dietary fiber to improve the lipid profile. However, there is a lack of quality trials.


Upper respiratory tract infections : S. cerevisiae 500 mg daily has been used in clinical trials over 12 weeks to treat respiratory infections and allergic rhinitis. Laxative : 6 to 50 g of fresh baker's yeast over 3 days was used in a study for the treatment of cancer-related constipation. Acute diarrhea : 500 mg daily of brewer's yeast is recommended in the German Commission E Monographs .


Crohn disease; concomitant monoamine oxidase inhibitor (MAOI) therapy.


Information regarding safety and efficacy in pregnancy and lactation is lacking.


Brewer's yeast contains tyramine. Avoid concurrent use with MAOIs.

Adverse Reactions

Mild GI symptoms, including flatulence.


Information is limited. Baker's yeast has Food and Drug Administration (FDA) GRAS (generally recognized as safe) status.

Brewer's yeast is most commonly produced from S. cerevisiae , a simple eukaryotic cell, but sometimes the related Saccharomyces exiguous or Saccharomyces boulardii are used. Many different strains of the yeast exist, and preparations may be from different sources. As a health supplement, the deactivated yeast is utilized and is available in powder, flake, tablet, and liquid forms. A yeast extract is also manufactured commercially by adding salt to a yeast suspension, causing autolysis of the protein content. 1 , 2


Use of yeast in baking and brewing date to 2000 BC, with records found in Egyptian tombs. Traditionally, brewer's yeast has been used as a food supplement, especially as a source of vitamin B for vegetarians. It is also used as a protein supplement, energy booster, and immune enhancer, as well as in the treatment of diarrhea and acne. 1 , 2 , 3


S. cerevisiae serves as an abundant source of the B-complex vitamins, minerals, and proteins, while being notably low in fat and sodium. B vitamins include thiamine (B 1 ), riboflavin (B 2 ), niacin (B 3 ), pantothenic acid (B 5 ), pyridoxine (B 6 ), folic acid (B 9 ), and biotin (B 7 ). However, brewer's yeast does not contain vitamin B 12 and, therefore, does not fully substitute for the vitamins missing from a vegetarian diet. Minerals provided by brewer's yeast include selenium, chromium (one of the richest natural sources of chromium), and zinc. Additionally, the cell wall of yeast provides a better source of beta-glucan fiber than oats. 3 , 4 , 5 , 6

Uses and Pharmacology

Limited trials have been conducted on S. cerevisiae as a single ingredient preparation by a small pool of researchers. Studies have also focused on selenium- and chromium-enriched yeast preparations used in diabetes and cancer patients (see Selenium or Chromium monographs). 2

Animal data

Research reveals no animal data in the last 10 years regarding the use of the yeast S. cerevisiae in diarrhea. The low toxicity profile of brewer's yeast and widespread use as a food supplement make such data unimportant.

Clinical data

An open-label trial evaluated the effect of 6 to 50 g daily of fresh baker's yeast in cancer-related constipation. The authors suggest yeast fermentation in the intestine may induce water retention in the lumen similar to that of lactulose or sorbitol. 7 The symptomatic treatment of acute diarrhea is an indication for brewer's yeast listed in the German Commission E Monographs . 1

Immune effects
Animal data

S. cerevisiae –derived beta-glucan has been shown to enhance neutrophil antimicrobial functions in vitro and in animal studies and to reduce staphylococcal abscess formation in a guinea pig model. 6 , 8

Clinical data

Clinical trials using yeast-derived beta-glucan are limited. Reviews of the effects of beta-glucan on the immune system have been published for fungal, oat, and barley beta-glucan sources (see Beta-glucan).

Purified, soluble yeast beta-glucan given orally to healthy volunteers increased salivary immunoglobulin A (IgA), 8 as did brewer's yeast administered to people with allergic rhinitis. 9

Enhanced microbial killing by monocytes and neutrophils has been demonstrated in healthy volunteers after S. cerevisiae –derived beta-glucan ( Betafectin ) administration and in surgical patients. 10 , 11

Metabolic syndrome
Animal data

Research reveals no animal data in the last 10 years regarding the use of the yeast S. cerevisiae in metabolic syndrome, hypertension, or diabetes.

Clinical data

A clinical trial evaluated the effect of brewer's yeast 10 g/day over 12 weeks on the lipid and glucose profile of healthy adults. No difference was found for body weight, blood pressure, and cholesterol. A decrease in serum triacylglycerol was demonstrated, as well as improvements in the glucose tolerance test. 12 Similarly, total cholesterol was decreased in a study among 15 obese hypercholesterolemic men. 6

Respiratory effects
Animal data

An antiviral effect of S. cerevisiae –derived beta-glucan on swine influenza virus has been demonstrated. 13

Clinical data

A series of double-blind, randomized clinical trials evaluated the effect of S. cerevisiae 500 mg over 12 weeks on symptoms of colds in healthy adults. Among immunized participants, a decrease in the incidence and duration of symptoms was demonstrated, while in nonimmunized participants, a decrease in incidence was observed, with no effect demonstrated on duration and severity of symptoms. 14 , 15 The same researchers evaluated the effect of the same commercial product in allergic rhinitis and demonstrated a decrease in nasal congestion and rhinnorhea and an increase in salivary IgA during high pollen-count days. No effect on ocular discharges was demonstrated. 9

Other uses

Improved depression scores have been demonstrated after 2 weeks among healthy volunteers using 200 and 500 mg doses of yeast hydrolysate as a gum. Brain mapping after 3 days showed a profile of a stable psychological state. 3 In animals, brewer's yeast extract decreased the spleen weight and interferon and interleukin activity in mice with induced chronic fatigue syndrome. 5

S. cerevisiae has been evaluated for its effect on skin texture, 16 and in combination with other natural products for safety and efficacy in HIV patients. 17


Upper respiratory tract infections

S. cerevisiae 500 mg daily (as commercially available capsules) has been used in clinical trials over 12 weeks to treat respiratory infections and allergic rhinitis. 9 , 15


6 to 50 g of fresh baker's yeast over 3 days was used in a study for the treatment of cancer-related constipation. 7

Acute diarrhea

500 mg daily of brewer's yeast is recommended in the German Commission E Monographs . 1


Information regarding safety and efficacy in pregnancy and lactation is lacking.


S. cerevisiae contains tyramine, and, although case reports are lacking, concurrent use of yeast supplements with MAOIs should be avoided. 4 , 18

Adverse Reactions

The use of S. cerevisiae has not been studied in children. It should be avoided in individuals allergic to yeast. Mild adverse reactions have been reported, including flatulence and a laxative effect. 7

Increased disease activity has been demonstrated in a study evaluating S. cerevisiae yeast consumption in Crohn disease. The presence of antibodies to the yeast was demonstrated in a portion of study participants. 19


Research reveals little information regarding the toxicology of brewer's yeast. At 3 g/kg body weight, no toxic effects were observed in mice or rats. 1 Brewer's yeast has GRAS status with the FDA. 20

Purified, soluble yeast beta-glucan manufactured in Norway has shown no mutagenic or chromosomal toxicity, and no acute or delayed toxicity was observed in mice, rats, and pigs after oral or parenteral administration in preclinical studies. 8


1. Blumenthal M, ed. The Complete German Commission E Monographs . Austin, TX: American Botanical Council; 1998.
2. Moyad MA. Brewer's/baker's yeast ( Saccharomyces cerevisiae ) and preventive medicine: part I. Urol Nurs . 2007;27(6):560-561.
3. Lee HS, Jung EY, Suh HJ. Chemical composition and anti-stress effects of yeast hydrolysate. J Med Food . 2009;12(6):1281-1285.
4. Shils ME, Shike M, eds. Modern Nutrition in Health and Disease . 10th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006.
5. Takahashi T, Yu F, Zhu SJ, et al. Beneficial effect of brewers' yeast extract on daily activity in a murine model of chronic fatigue syndrome. Evid Based Complement Alternat Med . 2006;3(1):109-115.
6. Bell S, Goldman VM, Bistrian BR, Arnold AH, Ostroff G, Forse RA. Effect of beta-glucan from oats and yeast on serum lipids. Crit Rev Food Sci Nutr . 1999;39(2):189-202.
7. Wenk R, Bertolino M, Ochoa J, Cullen C, Bertucelli N, Bruera E. Laxative effects of fresh baker's yeast. J Pain Symptom Manage . 2000;19(3):163-164.
8. Lehne G, Haneberg B, Gaustad P, Johansen PW, Preus H, Abrahamsen TG. Oral administration of a new soluble branched beta-1,3-D-glucan is well tolerated and can lead to increased salivary concentrations of immunoglobulin A in healthy volunteers. Clin Exp Immunol . 2006;143(1):65-69.
9. Moyad MA, Robinson LE, Kittelsrud JM, et al. Immunogenic yeast-based fermentation product reduces allergic rhinitis-induced nasal congestion: a randomized, double-blind, placebo-controlled trial. Adv Ther . 2009;26(8):795-804.
10. Babineau TJ, Marcello P, Swails W, Kenler A, Bistrian B, Forse RA. Randomized phase I/II trial of a macrophage-specific immunomodulator (PGG-glucan) in high-risk surgical patients. Ann Surg . 1994;220(5):601-609.
11. Dellinger EP, Babineau TJ, Bleicher P, et al. Effect of PGG-glucan on the rate of serious postoperative infection or death observed after high-risk gastrointestinal operations. Betafectin Gastrointestinal Study Group. Arch Surg . 1999;134(9):977-983.
12. Li YC. Effects of brewer's yeast on glucose tolerance and serum lipids in Chinese adults. Biol Trace Elem Res . 1994;41(3):341-7.
13. Jung K, Ha Y, Ha SK, et al. Antiviral effect of Saccharomyces cerevisiae beta-glucan to swine influenza virus by increased production of interferon-gamma and nitric oxide. J Vet Med B Infect Dis Vet Public Health . 2004;51(2):72-76.
14. Moyad MA, Robinson LE, Zawada ET Jr, et al. Effects of a modified yeast supplement on cold/flu symptoms. Urol Nurs . 2008;28(1):50-55.
15. Moyad MA, Robinson LE, Zawada ET, et al. Immunogenic yeast-based fermentate for cold/flu-like symptoms in nonvaccinated individuals. J Altern Complement Med . 2010;16(2):213-218.
16. Gaspar LR, Camargo FB Jr, Gianeti MD, Maia Campos PM. Evaluation of dermatological effects of cosmetic formulations containing Saccharomyces cerevisiae extract and vitamins. Food Chem Toxicol . 2008;46(11):3493-3500.
17. Maek-a-nantawat W, Phonrat B, Dhitavat J, et al. Safety and efficacy of CKBM-A01, a Chinese herbal medicine, among asymptomatic HIV patients. Southeast Asian J Trop Med Public Health . 2009;40(3):494-501.
18. Howland RH. MAOI antidepressant drugs. J Psychosoc Nurs Ment Health Serv . 2006;44(6):9-12.
19. Barclay GR, McKenzie H, Pennington J, Parratt D, Pennington CR. The effect of dietary yeast on the activity of stable chronic Crohn's disease. Scand J Gastroenterol . 1992;27(3):196-200.
20. US Food and Drug Administration. Partial list of microorganisms and microbial-derived ingredients that are used in foods. . Updated June 22, 2009. Accessed April 11, 2011.

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