In the late 1970s and 1980s, there was a lot of talk about candida albicans, a common fungus found on the skin, in the mouth, intestinal tract, and the vagina. Specifically, there was the idea, promoted by a pair of doctors in the Southern United States, that an allergy to candida albicans was behind a host of symptoms, including:
- abdominal bloating
- bladder infections
- cravings for sugar or alcoholic beverages
- difficulty concentrating
- menstrual problems
- mood swings
- muscle and joint pain
- respiratory and ear problems
- unexpected weight gain
- "feeling bad all over"
According to doctors C. Orian Truss and William G. Crook of Birmingham, Alabama and Jackson, Tennessee respectively, it was difficult to find any symptom that couldn't be traced back to candida albicans. The pair referred to the newly-discovered condition as “candida-related complex,” “candidiasis hypersensitivity,” “chronic candidiasis,” “yeast allergy,” “yeast overgrowth,” “the yeast syndrome,” or simply as "candida" or "yeast problem." The pair suggested that one out of three Americans suffered from a yeast allergy and an entire supplement industry sprung up around "the yeast problem."
However, the real problem wasn't yeast—it was the science behind the supposed "yeast allergy." It turned out to be mostly bogus and state medical boards began fining and suspending the licenses of the doctors involved in promoting and treating candida. "I believe that practitioners who diagnose non-existent 'yeast problems' should have their licenses revoked," says Stephen Barrett, M.D., who has done extensive research in the area. "Some apply this diagnosis to nearly every patient they see." Does that mean yeast allergies don't exist? No, they do—they're just not nearly as prevalent as candida proponents would have people believe. Yeast allergies make up a tiny fraction of all allergies. Sources of a yeast allergy include:
- most bread and cereal products
- beer, wine, and some ciders
- stocks and gravies
- vinegar and foods like pickles that contain vinegar
- fermented foods such as ripe cheeses and sauerkraut
- anything that has been opened and stored for an extended period of time
A yeast allergy may present as a yeast infection, as they share many of the same symptoms. One big difference is that people with a yeast allergy will usually become noticeably fatigued after consuming yeast. Although symptoms of a yeast allergy may vary from person to person, they may include one or more of the following:
- abdominal swelling
- breathing difficulties
- joint pain
There is a common misconception that a yeast allergy is the cause of the red, blotchy skin that some people develop after drinking alcoholic beverages. In fact, the rash is most often related to sulphur dioxide, a common ingredient in alcohol which may activate reactions to other allergens such as wheat and sulphites. Sometimes histamines and tannins will trigger rashes as well. A yeast allergy will typically not cause a rash.
Yeast Allergy: Beer
Although yeasts in beer may cause an allergic reaction in a few people, studies have found that alcoholic drinks contain very low levels of yeast allergens.
Brewer's Yeast Allergy
A 2010 study from the University of Michigan at Ann Arbor found that brewer's yeast may actually reduce seasonal allergy symptoms in some people. Subjects given a supplement of dried, modified brewer's yeast suffered from nasal congestion two weeks shorter than usual than did those who were given a placebo.
Allergy to Baker's Yeast
Baker's yeast is one of the components of the hepatitis B vaccine and it was once thought that rare, yet severe allergic reactions (approximately one case per 600,000 doses) including difficulty breathing, hives, and low blood pressure were related to the yeast. Research didn't bear out the concerns, however.
There are several tests available to confirm yeast allergies including:
- skin prick test: a small drop of the suspected allergen is placed on the skin and pushed through the first layer of skin with a small needle
- intradermal skin test: a syringe is used to inject the suspected allergen underneath the skin
- blood or RAST test: measures the amount of the IgE antibody in the blood
- food challenge test: a person is given increasing amounts of a suspected allergen as a clinician watches for a reaction. This is considered the best way to test for most food allergies
- elimination diet: a person stops eating the suspected allergen for a period of time and then slowly introduces them back into their diet while recording any symptoms