Brewer’s yeast shows up in beer, bread, dietary supplements, lactation cookies, yeast-extract spreads, and a surprising number of fermented foods. It’s a single-celled fungus (the same species used in baking) that was originally a byproduct of beer brewing. Today it’s sold as a nutritional supplement and added to foods for its B-vitamin content, protein, and mineral profile.
Beer and Other Alcoholic Drinks
Beer is the most obvious home for brewer’s yeast. Ale yeasts and lager yeasts both belong to the same genus, with lager strains being a hybrid that ferments at cooler temperatures. During brewing, yeast converts sugars into alcohol and carbon dioxide, then settles out of the finished beer. That leftover yeast is collected, dried, and sold as the supplement you find in health food stores.
Beyond beer, brewer’s yeast plays a role in malt liquor and hard ciders, which rely on yeast-driven fermentation. Wine uses different yeast strains, but some overlap exists.
Foods That Contain Brewer’s Yeast
Brewer’s yeast appears in more products than most people realize:
- Yeast-extract spreads: Marmite, Vegemite, and similar products are made from concentrated brewer’s yeast. These are among the most brewer’s-yeast-dense foods you can eat.
- Leavened baked goods: Breads, muffins, croissants, and biscuits typically contain yeast, though most commercial baking uses baker’s yeast rather than brewer’s yeast specifically.
- Cereals and candy: Products containing malt (fermented barley made with yeast) carry trace amounts.
- Soy sauce: This fermented soy and wheat product uses yeast during production.
- Miso: Some varieties incorporate yeast in fermentation.
- Kombucha: Brewed from sugar, tea, yeast, and bacteria.
Yeast also grows naturally in small amounts on berries and grapes, though these aren’t significant dietary sources.
Supplements and Lactation Products
Dried, inactivated brewer’s yeast is widely sold as a powder, tablet, or flake supplement. It’s a source of B vitamins, protein, fiber, and the mineral chromium. Supplement doses typically range from 500 mg to several grams per day.
Lactation cookies and breastfeeding support products are one of the fastest-growing uses. These recipes almost always include brewer’s yeast as a key ingredient, based on the idea that a compound called beta-glucan in the yeast cell walls may help stimulate milk production. This mechanism has been demonstrated in lab and animal studies, but human evidence remains limited. In one clinical trial, breastfeeding women took 5 grams per day of a yeast-based product for four weeks to evaluate its effects.
How It Differs From Nutritional Yeast
Brewer’s yeast and nutritional yeast come from the same species but taste and behave very differently. Brewer’s yeast has a distinctly bitter flavor because it’s a byproduct of beer production, carrying hop and fermentation residues. Nutritional yeast is grown specifically as a food product on sugar-rich molasses, then killed during manufacturing. The result is a cheesy, nutty, savory flavor that people sprinkle on popcorn or stir into sauces.
Both provide B vitamins and protein. Nutritional yeast is often fortified with vitamin B12, making it popular with vegans. Brewer’s yeast naturally contains chromium, which nutritional yeast typically does not. If you’re buying yeast flakes at the grocery store for cooking, you’re almost certainly getting nutritional yeast. Brewer’s yeast is more commonly found in capsule or powder form in the supplement aisle.
Who Should Avoid It
Brewer’s yeast is high in purines, compounds your body breaks down into uric acid. If you have gout or are prone to uric acid buildup, brewer’s yeast can trigger flare-ups and is best avoided entirely.
The other major concern is tyramine. Brewer’s yeast and yeast-extract spreads like Marmite are considered high-tyramine foods. For most people this is irrelevant, but if you take a class of antidepressants called MAOIs, tyramine can become dangerous. MAOIs block the enzyme that normally breaks down tyramine in your body. Without that enzyme working, eating high-tyramine foods can cause a rapid, potentially serious spike in blood pressure. The Mayo Clinic lists brewer’s yeast among the foods to avoid while taking these medications.
People with yeast allergies or frequent yeast infections sometimes avoid brewer’s yeast as well, though the dried, inactivated form in supplements contains no live organisms.