budding yeast cells
1 / 15

What Is Yeast?

It’s a fungus. There are many kinds of yeasts. You use one type to make bread, another to brew beer. One called candida lives inside your body. If it grows out of control, you can get an infection. Yeast infections can strike your skin, feet, mouth, penis, or vagina. If your immune system is weak, you may be more likely to get one.

Swipe to advance
digestive system illustration
2 / 15

It Keeps Things Running

You can get plenty of proteins and B vitamins from yeast-rich foods. Yeast keeps your digestive system healthy and in balance. The right amount in your body helps your immune system do its job. Yeast is part of a healthy mix of bacteria in your gut. It can help you absorb vitamins and minerals from your food, and even fight disease.

Swipe to advance
mouth sores
3 / 15

It Can Get Out of Balance

A little yeast in your body is good for you. Too much can cause infections and other health problems. If you take antibiotics too often or use oral birth control, your body might start to grow too much yeast. This often leads to gas, bloating, mouth sores, bad breath, a coating on your tongue, or itchy rashes.

Swipe to advance
young woman holding her baby
4 / 15

Your Immune System's Involved

If your immune system isn’t at its best, yeast can overgrow in your body. Babies, older people, and those with diseases like diabetes or HIV infection can have weakened immune systems. Chemotherapy for cancer and steroids can zap your immune system, too. Sjogren’s syndrome, which affects your immune system, can raise your risk of yeast infection.

Swipe to advance
candida albicans
5 / 15

All About Candida

It's the yeast most often to blame for health problems. Candida albicans is the most common strain. But there are least 20 candida species that cause infections in humans. Candida auris is a new fungus in this family that’s a big concern. Hospital patients infected with it can get very ill and may not get help from antifungal drugs.

Swipe to advance
candidiasis tongue
6 / 15

What Is a Yeast Infection?

If yeast is out of balance, you might get candidiasis, or a yeast infection. These most often affect your vagina, but you can also have thrush, a yeast infection in your mouth or throat. Too much yeast can trigger diarrhea or a skin rash. It’s rare, but if yeast overgrows and gets into your blood, it could cause infection throughout your whole body.

Swipe to advance
young woman wearing jeans close up
7 / 15

Yeast Infection Signs

It has some telltale symptoms. Your vagina might burn and itch. You may spot a thick, white discharge that looks like cottage cheese. It won’t have an odor. It might hurt when you pee or have sex. Thrush can cause white clumps inside your cheeks or on your tongue. Your mouth looks red, and it may burn so much that it’s hard to swallow food.

Swipe to advance
allergic skin reaction close up
8 / 15

Is Yeast Allergy a Thing?

Yes. Some people are allergic to yeast in foods like bread, vinegar, and beer. It can cause hives on your skin. A severe yeast allergy could make it hard to breathe or cause your throat to swell. You’ll need to work with your doctor to figure out which yeasty foods cause an allergic reaction and cut them out of your diet. Baked goods leavened with yeast are common culprits.

Swipe to advance
mouth sores
9 / 15

Nutritional Yeast

Nutritional yeast doesn’t cause infections. It’s good for your body. It’s rich in B vitamins that help you break down foods for energy. Zinc and iron in yeast build stronger bones and muscles. Nutritional yeast isn’t the same as brewer’s yeast. You can find it at a health-food store baked into crackers or chips. Sprinkle nutritional yeast on your popcorn or homemade sauces.

Swipe to advance
brewery pouring beer
10 / 15

Brewer’s Yeast

It’s used to make beer. It can also grow on corn or other grains. It’s rich in protein, B vitamins, and the mineral chromium, which helps keep your blood sugar levels in balance. Brewer’s yeast has a bitter taste. It might ruin the flavor if you sprinkle it on foods.

Swipe to advance
red yeast rice
11 / 15

Red Yeast Rice

Not really yeast but a cultured grain, it’s used in Chinese medicine to lower cholesterol. Red yeast rice products could be risky for your health, so it’s best to avoid them. They may interact with cholesterol drugs called statins or cause the same side effects. Some red yeast rice products also contain citrinin, which could lead to kidney failure.

Swipe to advance
kombucha drink
12 / 15


This popular drink made with yeast is a fermented tea with sugar added for taste. While some people claim kombucha prevents cancer or controls high blood pressure, there’s little proof that it really works. It can even make you sick if it’s brewed in a place that isn’t clean, whether that’s someone’s home or a shop.

Swipe to advance
homemade kefir
13 / 15


This fermented dairy treat comes from the Caucasus region of Turkey, but you can find it in most supermarkets now. Kefir is made by adding yeasty grains to milk. It’s a probiotic that helps keep your gut bacteria in balance. Kefir might help you treat diarrhea, irritable bowel syndrome, or eczema, although more research is needed. Low-fat dairy also builds strong, healthy bones.

Swipe to advance
bowl of kimchi
14 / 15

Fermented Foods

You can add fermented foods and drinks to your diet for their health benefits. Yogurt with live, active cultures is easy to find. Top it with fresh fruit for an extra boost. Sauerkraut, pickles, and kimchi are zesty fermented treats. But some of these foods are preserved for long shelf life, so they may also have lots of sugar or sodium.

Swipe to advance
yeast culture in petri dish
15 / 15

It Might Fight Cancer

New cancer drugs and screening tests that use yeast are in the works. Many genes involved in cancer are similar to those found in yeast, so they’re easier to map and study. One project is using yeast to create new drugs to treat aggressive breast cancer linked to the BRCA gene.

Swipe to advance

Up Next

Next Slideshow Title

Sources | Medically Reviewed on 11/16/2021 Reviewed by Kathleen M. Zelman, MPH, RD, LD on November 16, 2021


1) toeytoey2530 / Thinkstock

2) pixologicstudio / Thinkstock

3) mrfiza / Thinkstock

4) Purestock / Thinkstock

5) Dr_Microbe / Thinkstock

6) Adam88xx / Thinkstock

7) kieferpix / Thinkstock

8) areeya_ann / Thinkstock

9) post424 / Thinkstock

10) Gizmo / Thinkstock

11) alpaksoy / Thinkstock

12) Hendra Su / Thinkstock

13) alpaksoy / Thinkstock

14) Fudio / Thinkstock

15) Sinhyu / Thinkstock



Microbiology Online: “Fungi.”

DermNet New Zealand: “Candida.”

The Weston A. Price Foundation: “Nutritional Yeast.”

Nutrients: “Beneficial Effects of Probiotic and Food Borne Yeasts on Human Health.”

Journal of Probiotics & Health: “About the Journal.”

Current Opinions in Microbiology: “Inflammation and gastrointestinal Candida colonization.”

BioMed Research International: “Candida Infections, Causes, Targets, and Resistance Mechanisms: Traditional and Alternative Antifungal Agents.”

Contraception: “The impact of oral contraception on vulvovaginal candidiasis.”

Medscape: “Candidiasis.”

Mayo Clinic: “Do I need to include probiotics and prebiotics in my diet?” “Oral Thrush,” “Sjogren’s syndrome,” “What is kombucha tea? Does it have any health benefits? “Yeast infection (vaginal).”

Clinical Infectious Diseases: “Candida-associated diarrhea: a syndrome in search of credibility.”

CDC: “Candidiasis.”

GI Society/Canadian Society of Intestinal Research: “Yeast and Mould Allergy.”

National Center for Complementary and Integrative Health: “Red Yeast Rice.”

National Dairy Council: “What Is Kefir?

Tufts University Health and Nutrition Letter: “Discover the Digestive Benefits of Fermented Foods.”

Current Molecular Pharmacology: “Anti-Cancer Drug Discovery: Update and Comparisons in Yeast, Drosophila and Zebrafish.”

Reviewed by Kathleen M. Zelman, MPH, RD, LD on November 16, 2021

This tool does not provide medical advice. See additional information.

THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.