Having a yeast allergy or intolerance may mean that you have to cut yeast out of your diet. As in the case of other food allergies, this may be easier said than done because yeast is surprisingly common.
Many fresh fruits, vegetables and whole grains don’t contain yeast, as long as they haven’t been lying out in the open or started to spoil.
What Is Yeast?
NASA explains that yeast is a simple, unicellular form of fungi that has been used in the baking and fermentation processes for thousands of years. Baker's yeast and brewer's yeast are the two most common forms of yeast. Both strains originate from the Saccaromyces cerevisiae species of fungus.
Louis Pasteur was in fact one of the first people to begin experimenting with yeast, in the 1850s. Since then, there has been considerable research into the properties of yeast. A May 2018 study published in the journal Yeast notes that scientists' understanding of yeast has increased dramatically in the last three to four decades, allowing them to genetically modify its genome in order to serve various biotechnical purposes.
What makes yeast an important ingredient in products like bread and beer is the way it respires. When yeast is supplied with both sugar and oxygen, it multiplies exponentially. NASA notes that just 2 pounds of yeast can raise 500 pounds of bread dough. In the absence of oxygen, yeast ferments carbohydrates, which results in the production of ethanol (alcohol) and carbon dioxide.
According to NASA, yeast is in fact quite healthy and is sometimes even consumed as a nutrition supplement because it is 50 percent protein and is a good source of B vitamins like folic acid and niacin.
Yeast Allergy and Intolerance
The Mayo Clinic explains that a food allergy is an immune reaction that is triggered by eating a certain food. Even consuming small amounts of the food can cause hives, digestive problems or swollen airways. If the allergy is severe, it can cause a life-threatening reaction called anaphylaxis.
The Mayo Clinic explains that food allergies are not to be confused with food intolerance, which is a more common but less severe reaction that doesn't involve the immune system.
You should consult your doctor if you think you have a yeast allergy, because it can have severe consequences. Your doctor will be able to confirm whether a yeast allergy is causing your symptoms and rule out other conditions.
The Mayo Clinic notes that some alternative medicine practitioners advise sticking to foods that don't contain yeast if you have yeast syndrome, a condition caused by excessive growth of a fungus-like species known as Candida albicans in the digestive system. Known as the Candida cleanse diet, this regimen involves eliminating yeast as well as foods like sugar, cheese and white flour.
Read more: How to Rid the Body of Too Much Yeast
Yeast Food List
It's only when you start searching for a list of foods that don't contain yeast that you realize just how many of the foods you eat on a daily basis contain yeast. Keeping a yeast food list handy and checking food labels can help you avoid this organism.
It's probably no surprise that bread and other baked goods like croissants, muffins, bagels, biscuits, pretzels, crackers and rolls are at the top of the yeast food list. However, the University of Nebraska-Lincoln notes that baking powder and baking soda are now commonly used as substitutes for yeast since they work much faster than yeast, so you should be able to find yeast-free baked goods.
Alternatively, you can substitute baked goods with whole grains like quinoa, brown rice, rolled oats and popcorn.
Read more: Foods to Eat if You Can't Have Yeast
Alcoholic beverages like beer, wine and cider usually contain yeast. However an article published in the Journal of the Academy of Nutrition and Dietetics in March 2013 suggests that distilled spirits, like vodka, whiskey, gin, rum and tequila, may be alright to consume.
The University of Michigan notes that many fermented foods like kimchi, pickles, sauerkraut, kefir, yogurt, buttermilk, cheese, miso and tempeh may have been fermented with bacteria and yeast. Cured meats, olives, tofu, condiments, sauces, salad dressings and other foods containing soy sauce or vinegar may also contain yeast.
Most fruits and vegetables are among the foods that don't contain yeast as long as they are fresh and are not starting to spoil. However some berries, grapes, mushrooms and dried fruits may have traces of yeast. Any food that has been opened and sitting around may have yeast.
- NASA: “Planets in a Bottle — More About Yeast”
- Mayo Clinic: “Food Allergy”
- Mayo Clinic: “What Is a Candida Cleanse Diet and What Does It Do?”
- University of Nebraska-Lincoln: “Baking Soda Versus Baking Powder”
- Journal of the Academy of Nutrition and Dietetics: “Is There a Diet for “Yeast Allergy”?”
- University of Michigan: “Fermented Foods”
- Yeast: “History of Genome Editing in Yeast”