Should You Purchase A Food Sensitivity Test?

Are food sensitivity test accurate?

Over the last few years, food sensitivity testing has become more and more popular in the realm of  health and fitness for clients trying to obtain a deeper look into their gut health, and understand how it may impact their fitness goals.

Before I proceed with this article I want it to be known that everything that will follow is intended for the healthy and fit population. This article is NOT designed to speak to those with clinically diagnosed food allergies, auto-immune conditions such as IBS or celiacs disease, or diagnosed food intolerances.

Now that we have that cleared up, there has been a lot of buzz in the media lately about food sensitivity testing. This testing is very popular among alternative health practitioners and “health gurus” who are looking for to provide options to help their clients with their gut.

We are even starting to see personal trainers, coaches, and healthy way of life clubs, provide these “take home” food sensitivity testing to their clients. These test range from $100 to $500 USD and are rarely covered by insurance (that should be the first red flag.)

But what does the research say about this type of testing?

Before we dig into the research I want to provide you a fundamental understanding on the science of immunity, so that the research will make more sense to you. The premise behind this testing in the alternative health communities are that food intolerances can lead to low grade inflammation and this may cause weight gain or inhibit fat loss.

The first problem with this claim is there is an abundance of research that shows excess adipose tissue can cause inflammation, but the research is really lacking when it comes to proving food sensitivities can cause unwanted weight gain.

Most of these tests are testing for IgG antibodies to various foods and can prey on an uneducated consumer who assumes just because they have an antibody response that they are allergic or intolerant to certain foods. But as the research will show us, that’s not the case.

For a detailed overview of how our immune system works, you can refer to this publication by the NIH, but for our purposes it’s important to know that our immune system is our protector against foreign invaders such as viruses and bacteria.

Part of our immune system is tasked with forming antibodies (protectors) to fight the invaders. There are three main antibodies we will be discussing. IgA which are the first line of defense against foreign substances.IgG antibodies will will respond to invaders making it past IgA antibodies. And finally there are IgE antibodies who are involved in responding to allergies.

The American Academy of Asthma, Allergy, & Immunity defines IgE antibodies as:“ If you have an allergy, your immune system overreacts to an allergen by producing antibodies called Immunoglobulin E (IgE)” 

Now you are probably saying to yourself: “Cool Bill-Nye, but what do I need to know?”

We know that IgE antibodies are responsible for inducing the immune and inflammatory responses such as coughing, sneezing, vomiting, etc and NOT IgG or IgA antibodies. Food allergies are causing an IgE reaction in the body.

So why is it then that these take home food sensitivity test are only providing feedback on IgG antibodies? The other reactions to food defined as food sensitivities or intolerances are referred to as non-immune reactions.

The AAAI sums it up perfectly with this statement: “IgG and IgG subclass antibody tests for food allergy do not have clinical relevance, are not validated, lack sufficient quality control, and should not be performed.” 

Here is another great quote from the position statement of The Canadian Society of Allergy and Clinical Immunology (CSACI):  “There is no body of research that supports the use of this test to diagnose adverse reactions to food or to predict future adverse reactions. The literature currently suggests that the presence of specific IgG to food is a marker of exposure and tolerance to food, as seen in those participating in oral immunotherapy studies. Hence, positive test results for food-specific IgG are to be expected in normal, healthy adults and children.” 

For those still in doubt, here’s one more: “[The] seemingly poor response to an IgG based diet confirms the widely held view to date that IgG testing for food intolerance is not of value. These results suggest that if IgG testing identifies food intolerances at all, it does so fortuitously and with an apparent low degree of accuracy.” 

In summary, the research from all the major medical boards and publications is pretty clear, these test lack validation for their proposed claims of diagnosing food sensitivities via IgG antibodies. As Dr. Robert Wood, an allergist at John Hopkins Hospital so eloquently put it: Immunoglobulin G tests “are completely useless and do dramatic harm because they may compel patients to unnecessarily avoid broad swaths of a healthy diet.”

As a Registered Dietitian, I couldn’t agree more with Dr. Wood. The problem with these tests (besides people wasting their money) is that consumers will be removing innocuous foods from their diets based on phony results. Thus creating unnecessary aversions and elimination of potential nutrients from their diets.

So please, if you are experiencing severe and violently abnormal GI symptoms after consuming foods, don’t go to your trainer for a test, go see a licensed GI specialist. If your trainer or coach is providing any type of advice in regard to treating a medical condition, or reviewing lab work and offering diagnostic feedback, this is unethical and illegal. Refer to licensed medical professionals only.