Some tests claim to determine your sensitivity to hundreds of foods and ingredients by measuring the “bioresonance” of your hair, an unproven technique used in holistic or complementary medicine that involves measuring the energy wavelengths coming from your body. Others measure the levels of certain antibodies, called IgG antibodies, in your blood.
Still other tests, called Alcat and MRT tests, require a blood draw from a lab and measure how the size of your blood cells change after exposure to food extracts in a test tube, said Dr. John M. Kelso, an allergist at Scripps Clinic Carmel Valley in San Diego.
Are food sensitivity tests accurate?
Aside from the breath tests that gastroenterologists sometimes use to diagnose certain intolerances, like those to lactose or fructose, there aren’t validated tests for food intolerances or sensitivities, said Tamara Duker Freuman, a registered dietitian at New York Gastroenterology Associates in New York City. The only way to figure out if you are sensitive to certain foods or ingredients is to see how your symptoms change after eliminating them from your diet, ideally with the help of a registered dietitian or physician, she said.
This can be a slow process involving trial and error, and the companies selling food-sensitivity tests market them as a shortcut. But medical organizations, including those in the United States, Europe and Canada, have recommended against using food sensitivity or intolerance tests because there is no good evidence that they work.
“There isn’t anything in your hair that would tell you anything about your sensitivity to food,” Dr. Kelso said. And the antibodies measured in the IgG tests are produced as part of the immune system’s normal response to foods; they haven’t been shown to correlate with symptoms or intolerances, Dr. Stukus said. “It’s really just a reflection of what you’ve eaten.”
Similarly, the way blood cells in a test tube interact with food extracts, as in the Alcat and MRT tests, is likely different from how they encounter them in the body, Dr. Kelso said. None of these tests have been subjected to the kind of high quality clinical trials necessary to validate their usefulness for patients, he added. (Oxford Biomedical Technologies, the company that sells a blood cell MRT test, did not respond to a request for comment.)