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.
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What Is Yeast?
Yeast is a simple fungus that has been used in the baking and fermentation processes for thousands of years, according to NASA. The two most common forms of yeast are baker's yeast and brewer's yeast. Both strains originate from the Saccharomyces cerevisiae species of fungus.
A May 2018 study 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 breathes. When yeast is supplied with both sugar and oxygen, it multiplies exponentially. Just 2 pounds of yeast can raise 500 pounds of bread dough, per NASA. In the absence of oxygen, yeast ferments carbohydrates, which results in the production of ethanol (alcohol) and carbon dioxide.
Yeast is quite healthy and is sometimes even taken as a supplement — aka nutritional yeast — because it is 50 percent protein and is a good source of B vitamins like folic acid and niacin, according to NASA.
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 it. Keeping a yeast food list handy and checking food labels can help you avoid this organism.
Generally, these foods do not contain yeast:
- Low-sugar fruits
- Herbs and spices
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.
But some berries, grapes, mushrooms and dried fruits may have traces of yeast. Any food that has been opened and sitting around may have yeast.
Foods With Yeast
Some common foods with yeast include:
Most baked goods, as well as wheat items like crackers, contain yeast. But baking powder and baking soda are now commonly used as substitutes for yeast because they work much faster than yeast, so you should be able to find yeast-free baked goods.
Some Types of Alcohol
Alcoholic beverages like beer, wine and cider usually contain yeast.
However, a March 2013 study in the Journal of the Academy of Nutrition and Dietetics suggests that distilled spirits, such as vodka, whiskey, gin, rum and tequila, may be OK on a yeast-free diet.
Fermented or Cured Foods
The University of Michigan states that many fermented foods, such as the following, 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.
Yeast Allergy and Intolerance
A food allergy is an immune reaction that is triggered by eating a certain food, per the Mayo Clinic. Even eating 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.
Food allergies are not to be confused with food intolerances, which is a more common but less severe reaction that doesn't involve the immune system.
Talk to 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.
Should You Cut Out Foods That Contain Yeast?
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, per the Mayo Clinic. Known as the Candida cleanse diet, this regimen involves eliminating yeast as well as foods like sugar, cheese and white flour.
But there's little scientific evidence that eliminating foods with yeast can improve the effects of yeast overgrowth in the body, per the Mayo Clinic.
- 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”