If you are dealing with symptoms such as hives or bloating, you may suspect a food allergy or sensitivity. But how can you determine which foods are causing the reactions?
If you search online for “food allergy testing,” you’ll find do-it-yourself test kits that claim to deliver comprehensive results (with a 100 percent money-back guarantee!). Not all of the methods are equally reliable, and some are downright fraudulent. There is no single test that will tell you exactly which foods to avoid.
• Allergy or sensitivity? It’s important to know the difference. A food allergy is an immune system reaction that can cause hives, wheezing, itching, diarrhea, vomiting, shortness of breath and anaphylaxis. About 3.6 percent of Americans have food allergies.
Food sensitivity or intolerance is a reaction that involves the digestive system, not the immune system. Symptoms include gas, bloating, nausea, vomiting and diarrhea. Although intolerances can be painful and uncomfortable, they are not life-threatening. Anywhere from 2 to 20 percent of Americans may be sensitive to certain foods. There are no precise numbers because there is no exact diagnostic test.
• For allergy: If you suspect a food allergy, don’t self-diagnose. Food allergies are much too serious to assess without an expert. Your best bet is a board-certified allergist, who will perform skin-prick tests and IgE blood tests to narrow down a diagnosis. (IgE, or immunoglobulin E, is a type of antibody produced by the immune system. More IgE is produced during an allergic reaction.) But keep in mind that even these tests are imperfect, and may falsely show you are allergic to something.
You may hear alternative practitioners talk about other tests such as hair analysis, IgG tests (which measure immunoglobulin G, another antibody produced by the immune system), facial thermography and muscle testing. The National Institute of Allergy and Infectious Diseases says these tests “lack evidence demonstrating any value in diagnosing food allergies.” They also can set you back a few hundred dollars each, and you might endanger your health with inaccurate results.
The gold-standard food allergy test is an oral food challenge done in partnership with your allergist, which may be done in conjunction with IgE and skin-prick tests. For an oral food challenge, you will eat small amounts of the suspected allergen and watch for a reaction in the safety of the doctor’s office (with antihistamines and epinephrine on hand in case of serious reactions).
• For sensitivity: Unfortunately, there are no validated tests to diagnose food sensitivity, even though marketing leads consumers to think many test methods are accurate and reliable. Don’t believe the hype.
If you suspect a food sensitivity, an elimination diet is the most reliable way to determine your trigger foods. In consultation with your doctor or dietitian, you will remove foods from your diet that you suspect are causing reactions such as gas and bloating. You will later reintroduce the foods one at a time, and keep track of symptoms. And hey, no fancy kits to buy!