Who Should Not Use Brewers Yeast? A Comprehensive Guide

November 14, 2025 •

4 min read

An estimated 45 million Americans use nutritional supplements, but many are unaware of potential contraindications. It is crucial to understand who should not use brewers yeast before adding it to your routine, as it can cause adverse reactions or dangerous interactions with certain health conditions and medications.

Quick Summary

This guide outlines the critical health conditions and medications that contraindicate brewers yeast use. It details risks for individuals with compromised immunity, autoimmune diseases like Crohn's, diabetes, and those on specific antidepressants or antifungals, emphasizing the importance of medical consultation.

Key Points

Compromised Immune Systems: Individuals with conditions like HIV/AIDS, cancer, or organ transplants are at high risk of fungal infection from brewers yeast.
Yeast Allergies and Infections: Anyone with a known yeast allergy or a history of recurrent yeast infections (like Candida) should avoid brewers yeast.
Inflammatory Bowel Disease: Patients with Crohn's disease or ulcerative colitis should not use brewers yeast, as it can worsen inflammation and trigger flares.
Drug Interactions (MAOIs): Brewers yeast contains tyramine, which can cause a hypertensive crisis in those taking monoamine oxidase inhibitor antidepressants.
Diabetic Risk: Due to its blood sugar-lowering effects, brewers yeast can cause dangerous hypoglycemia when combined with diabetes medications.
Gout Flare-ups: The high purine content in brewers yeast can increase uric acid levels and lead to painful gout attacks.
Consult a Doctor: It is essential to consult a healthcare provider before taking brewers yeast to ensure it is safe for your specific health conditions and medications.

Critical Conditions and Contraindications

While brewers yeast is a popular nutritional supplement rich in B-vitamins and chromium, it is not safe for everyone. The potential health risks, especially for individuals with certain pre-existing conditions, make it essential to understand the contraindications. This section details the primary reasons why some people must avoid brewers yeast entirely.

Compromised Immune Systems

Individuals with weakened or compromised immune systems should avoid brewers yeast. This includes people with conditions like HIV/AIDS or cancer, as well as those who have recently undergone an organ transplant and are taking immunosuppressant medications. The concern is that the live Saccharomyces cerevisiae yeast found in some supplements could potentially trigger a systemic fungal infection in individuals unable to effectively fight it off. In such cases, the opportunistic yeast can overgrow, leading to serious and life-threatening complications. Even non-active, or 'killed', forms should be used with caution and only under a doctor's supervision.

Yeast Allergies and Recurrent Infections

For those with a known allergy to yeast, taking a brewers yeast supplement is an obvious and serious risk. Allergic reactions can range from mild symptoms like itching and hives to severe anaphylactic responses, including chest tightness, trouble breathing, and swelling of the throat or face. Furthermore, individuals who suffer from recurrent yeast infections, such as Candida, should also avoid brewers yeast. While brewers yeast is a different species, some studies suggest that in those prone to fungal infections, the supplement could potentially worsen or trigger new outbreaks.

Inflammatory Bowel Diseases (IBD)

People diagnosed with inflammatory bowel diseases like Crohn's disease or ulcerative colitis should not use brewers yeast. Research has shown that individuals with Crohn's often have higher levels of antibodies to Saccharomyces cerevisiae, the yeast species in brewers yeast. While the exact mechanism is still debated, some studies indicate that taking brewers yeast could exacerbate inflammation and trigger flares in Crohn's patients. Animal studies have also suggested it may worsen these conditions.

Medication Interactions and Metabolic Risks

Beyond specific health conditions, brewers yeast can also interfere with certain medications and impact metabolic functions, necessitating caution or complete avoidance.

Monoamine Oxidase Inhibitors (MAOIs)

Brewers yeast contains a significant amount of tyramine, an amino acid that helps regulate blood pressure. When combined with monoamine oxidase inhibitors (MAOIs), a class of medications used to treat depression, the body cannot break down tyramine properly. This can lead to a sudden and dangerous spike in blood pressure known as a hypertensive crisis, which can increase the risk of heart attack or stroke. Examples of MAOIs include isocarboxazid, phenelzine, and selegiline.

Diabetes Medications

Brewers yeast, especially variants high in chromium, can help lower blood sugar levels. While this may sound beneficial for some, it poses a serious risk for individuals already on diabetes medication, such as insulin, metformin, or sulfonylureas. The combination can cause a dangerously low blood sugar level, known as hypoglycemia, which can be life-threatening. Any diabetic considering brewers yeast should consult their doctor for careful monitoring and potential dosage adjustments.

Antifungal Medications

Because brewers yeast is a fungus itself, taking it while on antifungal medications like fluconazole (Diflucan) or terbinafine (Lamisil) can reduce the effectiveness of the medication. The antifungal drug is designed to kill fungal cells, and consuming brewers yeast may counteract the treatment.

Gout

Brewers yeast is a rich source of purines, compounds that the body breaks down into uric acid. High levels of uric acid are the direct cause of gout, a painful form of arthritis. For this reason, individuals with gout or a predisposition to it should avoid brewers yeast to prevent flare-ups.

Comparison: Brewers Yeast vs. Other Supplements


Feature	Brewers Yeast	Nutritional Yeast	Probiotic Supplements
Origin	Byproduct of beer brewing, containing Saccharomyces cerevisiae.	Grown specifically for nutritional purposes; deactivated.	Contain live, beneficial bacteria or yeast, specific strains may vary.
Tyramine Content	High; significant concern for those on MAOIs.	Usually low or non-existent; safer for those sensitive to tyramine.	Dependent on specific strain; generally not a concern unless specific yeast strain is added.
Risks for IBD	Contraindicated for Crohn's and ulcerative colitis.	Generally considered safe and may offer benefits for some digestive issues.	Specific strains like Saccharomyces boulardii are often used to treat diarrhea.
Immune Compromise Risk	High risk of systemic infection; contraindicated.	Deactivated yeast poses no infection risk from the supplement itself.	Use caution; specific strains and dosages should be medically supervised.

Conclusion: When in Doubt, Consult a Professional

In conclusion, while brewers yeast offers several nutritional benefits, the list of contraindications and potential interactions is significant. Who should not use brewers yeast includes people with compromised immune systems, yeast allergies, inflammatory bowel diseases like Crohn's, and those taking MAOIs or diabetes and antifungal medications. Individuals with gout also face increased risk due to its high purine content. Given the complexities and potential for serious side effects, the most prudent course of action is to always consult with a healthcare provider before starting any new supplement, including brewers yeast. This ensures its safety and appropriateness for your specific health profile.

Visit Healthline for more detailed information on brewers yeast.

Frequently Asked Questions

You should not use brewers yeast without strict medical supervision if you have diabetes. It can lower blood sugar levels and, when combined with diabetes medication, can lead to dangerously low blood sugar (hypoglycemia).

Brewers yeast does not typically cause vaginal yeast infections in healthy individuals. However, individuals who have recurrent fungal infections, particularly Candida, should avoid it, as it may exacerbate their condition.

No, individuals with certain autoimmune diseases like Crohn's disease and ulcerative colitis should avoid brewers yeast, as it is known to potentially trigger or worsen symptoms.

For those with compromised immunity, the live yeast in some supplements could cause a systemic fungal infection that the body is unable to fight. This is a serious risk for people with HIV/AIDS or cancer.

If you are taking monoamine oxidase inhibitor (MAOI) antidepressants, you must avoid brewers yeast. The high tyramine content can cause a severe hypertensive reaction.

There is not enough reliable information to determine the safety of brewers yeast during pregnancy or breastfeeding, so it is recommended to avoid it.

Brewers yeast is high in purines, which increases uric acid levels in the body. This can trigger painful gout attacks, so it should be avoided by people with this condition.