Reliability of Food Sensitivity Testing

By Heather Irwin, MS, RD, LDN

At Bodymetrix, we see a wide variety of clients. Some are looking to lose weight or eat healthier. Some may have health concerns such as diabetes or heart disease. There are also plenty of patients who find that certain foods don’t agree with them and they come to us to try to figure this out. I am finding a lot of these clients have already used a food sensitivity test kit which inevitably gives them pages full of restrictions that they plop on my desk as they say, “Help, there is nothing left for me to eat!!!” I have found that these test kits have become a confusing distraction instead of actually helping and giving actionable answers.

You may have seen these tests advertised on social media or an alternative health practitioner. I know someone that purchased one from Groupon!! These tests generally require a blood draw while some use saliva or hair follicles. Some of them can only be ordered by licensed health care providers and others can be ordered online and sent directly to your home.

A typical scenario that plays out in my office is a client comes in after completing one of these tests. They may have more than 30 foods that are currently part of their diet which they need to avoid. Usually gluten, dairy, and soy are always included. The client then works diligently to eliminate all of these foods and sometimes they feel better, but sometimes they don’t. Regardless of how they feel, they soon realize that they can’t keep up with this highly restricted diet.

Let’s start by going over some reasons why you might not feel well after eating. According to the American Academy of Allergy, Asthma, and Immunology, a food intolerance/sensitivity takes place in the digestive system. It happens when you aren’t able to break down the food you eat. This can be caused by enzyme deficiencies, sensitivity to a food, or a reaction to naturally occurring food chemicals. Typically people with an intolerance can eat these foods in small amounts without experiencing problems. A food allergy, however, involves the immune system. If you have an allergy to milk, your immune system experiences the milk as an invader or an allergen. In response, your immune system produces antibodies and then an allergic reaction ensues such as hives, swelling, and worse case anaphylaxis. One important distinction between intolerance and allergy is with an allergy, eating a small amount can cause a serious, sometimes life threatening reaction.

Food allergy occurs in about 1-2% of adults and less than 10% of children. The most common food allergies are peanut, tree nut, milk, egg, wheat, soy, fish and shellfish.

There is currently NO SCIENCE BASED test to diagnose a broad spectrum of food intolerances. The best way to determine if someone has a possible food sensitivity or intolerance is to take a detailed history of symptoms and suspected foods, eliminate that food for 2-4 weeks, then a reintroduction of that particular food to see if symptoms return.

The take away here is that if you suspect you may have a true food allergy, board certified allergists are the best type of specialist to determine if a food allergy is present. If you suspect an intolerance or sensitivity, a Registered Dietitian can help evaluate your diet with you to see what food(s) may be bothering you.

Source:, American Academy of Allergy, Asthma, and Immunology

Heather Irwin, MS, RD, LDN
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