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Alyssa Simpson RD, CDE, CLT
Alyssa Simpson

(602) 422-9800

Sibo Doctor Approved
certified gastrointestinal nutritionist
Sibo Doctor Approved
certified gastrointestinal nutritionist

Will Food Sensitivity Testing Help You Feel Better? Let’s Cut Through the Confusion

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You’ve probably been seeing ads for food sensitivity testing all over the place lately. People are catching on that food sensitivities are a real thing. And they matter.

I’m not talking about food allergies. Food allergies are more acute than sensitivities and often result in severe or even life-threatening symptoms.

Food sensitivities are very common, but often go undetected. The symptoms are less obvious than a food allergy. And unlike an allergy, symptoms of a food sensitivity can show up hours or even days after the offending food is consumed.

If you’d like to learn more about food allergies, sensitivities, and intolerances, check out this article.

If you or your practitioner suspect you have food sensitivities, you’ll want to figure out which foods are causing you problems. Unfortunately, this isn’t that simple.

Some people try the food journal approach. And while this can work well for food intolerances and even allergies, it’s not very effective for revealing food sensitivities.

Since symptoms can show up so far after-the-fact, it can be really hard to figure out which foods you are struggling with just by journaling. Also, sensitivities can have a dose-related and combined effect, making identifying them even more difficult. So it’s really a guessing game.

But, there is a better way…

There are tests for food sensitivities. A lot of them actually. But many tests on the market are ineffective and inconclusive.  

How does food sensitivity testing work?

Food sensitivities develop when your body tags a specific food protein as a hostile invader. When this happens, your immune system responds every time you eat that food.

Food sensitivity testing evaluates your immune response to certain foods. And this, in theory, can help you and your practitioner figure out which foods which foods are causing inflammation in your body.

But many of the food sensitivity tests out there don’t really provide definitive answers. Some give unreliable results — false positives or negatives. And some make assumptions about the immune response to foods that may not be accurate. Just because you have certain antibodies or other immune agents in your blood doesn’t always mean you have an issue with the food being tested.

As a practitioner who helps clients with food sensitivities on a daily basis, I get EXTREMELY FRUSTRATED by all the inaccurate tests that are giving people unreliable information. So let’s break down what’s out there.

IgG Testing 

It’s fairly easy to get your hands on an IgG test for food sensitivities. Everlywell sells an at-home version that you can order, administer yourself, and then mail back in. Sounds good, right? 

Unfortunately, this type of testing has never been scientifically proven to provide accurate food sensitivity results.

IgG testing checks your blood for specific antibodies (IgG). In theory, if you have antibodies that relate to a specific food, then you are sensitive to that food. This seems logical. But the presence of IgG antibodies has never been scientifically proven to indicate food sensitivities. The presence of these antibodies may be a normal response to particular foods. Or it’s possible that their presence means your body is equipped to tolerate these foods well.

Plus, IgG is highly correlated with exposure. So if you eat a lot of a certain food — even if you’re not sensitive to it — it’s more likely to get flagged on an IgG test as a sensitivity.

Even if these tests are effective at finding IgG antibodies for foods, the results are very limited. Tests like Everylywell and ELISA/IgG are only looking at one possible mechanism involved in food sensitivities. They fail to account for the other immune reactions, such as IgM, complement, and T-cell reactions. And since IgG can be either pathogenic or a protective antibody, its mere presence doesn’t tell us much.

The ALCAT Test 

The ALCAT claims to measure sensitivities to foods at the cellular level. But this is an outdated technology with limited accuracy. It cannot test an immune response called T-cell reactions. ALCAT also has poor split sample reproducibility and therefore is not considered a reliable test.

Both the ALCAT and IgG tests have been discredited by allergy and immune organizations the world over — from America to South Africa to Australia to Europe, and beyond. 


Serammune Physicians Lab’s ELISA/ACT Test, developed by Russell Jaffe, M.D., Ph.D., claims to locate “hidden allergies”. This test looks exclusively at your lymphocytes (a white blood cell that’s part of the immune system).

The ELISA/ACT test claims a high accuracy and reproducibility for food sensitivity testing. And while it can measure certain immune responses, the results are not necessarily related to food sensitivities.

ELISA/ACT’s greatest strength is their promotion and marketing efforts. Yet there are no published studies supporting their position. In fact, the prominent scientific publications referenced in their marketing materials make no mention of ELISA/ACT. 

MRT Test 

This is the test I use in my practice. So (spoiler alert) — I trust it.

The MRT (Mediator Release Test) pinpoints the foods and chemicals that cause the cells to react and release mediators — powerful chemicals that negatively affect the body. These mediators are the chemicals that actually cause the symptoms associated with food insensitivities.

Patented by Signet Diagnostic Corporation in 2001 (now Oxford Biomedical Technologies), the MRT test is the most effective tool we have. It identifies not only which foods a patient is reacting to, but the degree of reactivity. 

The MRT tests for 140 foods and 30 chemicals and additives by precisely measuring how the blood reacts to samples of each substance being tested.

The MRT test has a 94% sensitivity and 92% specificity. And it’s extremely reliable. It boasts a split sample reproducibility consistently greater than 90%. That’s science-speak for, “this test ACTUALLY WORKS, and produces reliable results.”

Part of the reason I like the MRT is that It’s an end-point test. It doesn’t focus on only one chemical response. It measures a variety of immune-related chemicals — all the possible non-IgE reactions, including IgG, IgM, complement, and T-cell reactions. 

The MRT doesn’t just tell me which foods my patients are reacting to. It also identifies the foods that are the BEST for them to eat. So once the MRT results are in, I can work with my patients and develop an eating plan that isn’t just about avoiding foods. It’s about finding the foods that are beneficial and enjoyable. This personalized program is called LEAP (Lifestyle Eating and Performance).

Using the MRT results, the LEAP program provides a diet protocol designed to rid the patient of symptoms within the first 10-14 days of treatment. Then it phases the patient into a diet protocol designed to prevent future food sensitivities from developing.

If you’re ready to get to the bottom of your food sensitivities so you can start feeling better, food sensitivity testing may be a great fit for you. But choose wisely. The wrong information can send you onto a restrictive diet that does more harm than good.

When you are eliminating foods from your diet, it’s always a good idea to work with an experienced practitioner. Every body has different needs. And if you start to eliminate foods without knowing your nutritional deficiencies, you can send yourself further down the spiral of symptoms.

If you’re interested in finding out if the MRT is right for you, I’d be happy to talk with you. Click the link below to book a consultation. Let’s get to the bottom of your symptoms and get you feeling better!

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