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Do Home Tests for Food Sensitivity Work?

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Sally Kuzemchak, MS, RD - Blogs
By Sally Kuzemchak, MS, RDRegistered dietitianMarch 22, 2019

Ads for at-home food sensitivity tests seem to be all over social media right now. With just a drop of blood (and about $150), companies claim to be able to test your sensitivity to dozens of foods and tell you which ones are causing symptoms ranging from acne to joint pain. If you’re thinking about trying one, here’s what you should know first.

These tests typically measure IgG, an antibody produced by the immune system. According to one popular test’s website, an IgG response can contribute to headaches, joint pain, eczema, and other chronic problems.

But the presence of these antibodies doesn’t necessarily mean your body is having trouble with that food or that those foods are triggering any problems. Producing IgG antibodies is a response that’s actually linked to a tolerance and familiarity to the food, not an intolerance, according to an article in The Journal of Allergy and Clinical Immunology: In Practice. According to the Canadian Society of Allergy and Clinical Immunology’s position statement on these kinds of tests, you’d expect to see positive test results for food-specific IgG in normal, healthy adults and kids.

Trouble is, the folks I see on social media sharing their results seem to think that if they test positive for a certain food, they have to avoid it. Yet someone’s test results could show a lengthy list of foods, including nutritious staples. Eliminating those healthy favorites from the diet may not only be unnecessary but also unhealthy, and lead to restrictive eating. In my research for this post, I tried the test too. It came back showing a high reactivity to peanut, something I eat and enjoy nearly every day, and a mild reactivity to 22 different foods including yogurt, oats, watermelon, wheat, and broccoli.

Another issue: The symptoms, according to the testing kit, that are supposedly caused by IgG responses are so broad and vague, it’s hard to know if it’s what you’re eating or something else in your routine or another medical concern. Are your headaches triggered by eggs—or because you’re stressed or not getting enough sleep? Is your skin breaking out from eating wheat--or from hormonal fluctuations or your new moisturizer?

If you suspect that you’re reacting poorly to something you’re eating, one option is to play detective yourself. Keep track of what you eat and take note when your symptoms occur and see if you can spot any patterns. Better yet, see a doctor or dietitian who can do a deeper dive into what’s going on and do further (proven) tests for conditions like celiac disease, lactose intolerance, and food allergies. If you have irritable bowel syndrome, it’s also possible you’re reacting to certain types of carbohydrates and could identify them using a low-FODMAPS diet.

But in the meantime, be wary of the claims you see that a simple at-home test can give you answers.

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About the Author
Sally Kuzemchak, MS, RD

Sally Kuzemchak is a registered dietitian in Columbus, Ohio. An award-winning reporter and writer, Sally has been published in magazines such as Health, Family Circle, and Eating Well and is a Contributing Editor to Parents magazine. She is the author of the book The 101 Healthiest Foods For Kids. She blogs at Real Mom Nutrition, a “no-judgments” zone all about feeding families.

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