THE MYTH OF FOOD SENSITIVITY TESTING
THE MYTH OF FOOD SENSITIVITY TESTING
by Claire Allen, RD
There are many food sensitivity tests on the market that claim to identify food intolerance, leaving patients wondering if they are scientifically valid and worth their hefty cost. It is important to distinguish between food allergy and food sensitivity or intolerance and what the science shows (or doesn’t) for the tests on the market.
Food allergies are the body’s immune response to a protein in a food. Allergies are mediated by the antibody immunoglobulin E (IgE), which the immune system makes in reaction to a food. The purpose is to protect the body from what is perceived as a threat. IgE mediated reactions often occur immediately after the food is consumed and can cause symptoms such as hives, swelling, vomiting and in serious cases anaphylaxis. The patient often experiences the same response every time they ingest the food.
Food intolerance/food sensitivity is not an immune system reaction but relates to trouble digesting foods. This may be due to the lack of an enzyme needed to digest certain foods (such as lactose intolerance) or trouble digesting short-chain carbohydrates such as FODMAPs. Symptoms tend to be more predominant in the gut, such as bloating, gas, belching or altered bowel patterns. Reactions are not always consistent and may also depend on the quantity of the food consumed or other foods eaten that day.
Food sensitivity tests often test for immunoglobulin G (IgG) antibodies, which reports IgG levels to multiple foods (up to 100 foods within a single test panel). Common claims indicate the removal of foods with high IgG levels will lead improvement to multiple symptoms such as irritable bowel syndrome. Per the statement from the American Academy of Allergy, Asthma and Immunology, “this test has never been scientifically proven to be able to accomplish what it reports to do. The scientific studies that are provided to support the use of this test are often out of date, in non-reputable journals and many have not even used the IgG test in question. The presence of IgG is likely a normal response of the immune system to exposure to food. In fact, higher levels of IgG4 to foods may simply be associated with tolerance to those foods.”
Due to the lack of evidence to support its use, many reputable organizations have recommended against using IgG testing to diagnose food allergies or food intolerances / sensitivities. The ‘gold standard’ to determine a food sensitivity or intolerance should be a food elimination and challenge, guided by a trained registered dietitian. If you feel that you have undiagnosed food intolerance, schedule an appointment with one of our specialized registered dietitians to help lead you on your path to recovery. Call today at 224-407-4400 or visit our website at www.compgihealth.com.