There has been increasing concern regarding food intolerances over the past several years, and people are often confused regarding the difference between a food intolerance and a food allergy. Food allergies (especially the immediate type of food allergies of which most people are aware) can cause life-threatening reactions (anaphylaxis) while food intolerances are not life threatening. There are no standardized tests for food intolerances, and while companies may offer testing for food intolerances, no one actually knows what the testing means. These tests measure “IgG” antibody to foods and do not provide information about food allergies. Testing for “IgE” antibody to foods does provide information regarding food allergies. With food allergy tests (as with most tests) there can be false positives, so these tests should never be done indiscriminately and should only be done under the care of an allergy specialist. In fact, avoiding a food that someone tolerates without any symptoms based on a positive “IgE” test alone can actually lead to the development of life-threatening food allergies, so allergists strongly advise against random food allergy testing. Since there are no standardized tests for food intolerances, and since most tests for food intolerances show many positive results that do not correlate with a person’s symptoms, the best approach for most individuals is to keep a food and symptom diary to help them determine if a food intolerance (again, not a food allergy) is triggering their symptoms. Most patients who are healthy and have no symptoms will have IgG antibodies to one or more foods. Our practice, Allergy, Asthma & Food Allergy Centers of St. Louis, has a very, very strong focus on FOOD ALLERGY but not food intolerances. When patients come to see us about food intolerances, we generally advise against any form of allergy testing.
Please follow this link to watch Dr. Vitale on the news from 2/27/19 discussing food intolerance.