MRT Test for Food Sensitivities

Have you heard of the MRT test to address food sensitivities? Are you struggling with debilitating symptoms that are keeping you from enjoying the things that are the most important to you? Have you missed days at work or school or turned down social events because of the pain of migraines, IBS or arthritis? Has no one been able to give you any relief or answers? If any of these resonate with you, you may be dealing with food sensitivities, so keep reading!

What are Food Sensitivities?

Food sensitivities have become a hot topic over the last 5 years. Simply speaking they are adverse food reactions that cause inflammation. Inflammation most of the time starts in the gut which is why gut health and food sensitivities are so closely connected. That’s because 2/3 of the immune system is housed there!  But keep in mind, not all adverse food reactions involve the immune system. 

Contrary to popular belief, food sensitivities are different than food intolerances and food allergies which means the testing is different as well! The collection of these three all fall under the umbrella term of an adverse food reaction. Let’s breakdown each:

Food Allergy

  • Immune mediated reaction that is generally immediate. Within 30 minutes of food consumption. 
  • Diagnosed by a blood test or skin prick test.
  • Symptoms most often impact the skin, lungs, throat, and GI tract. Anaphylaxis is the most severe reaction of a food allergy.

Food Intolerance

  • No immune reaction, simply due to a lack of an enzyme. For example, lactose intolerance. 
  • Symptoms generally within a couple of hours.
  • Diagnosed by a breath test.
  • Symptoms impact only the digestive tract. For example, gas, bloating, nausea, diarrhea, constipation. Another symptom is called borborygmi, also known as gurgling sounds. Try and pronounce that word 5 times!

Food Sensitivity

  • Immune mediated reaction that can be immediate or delayed up to 72 hours which makes identifying them difficult.
  • Diagnosed by blood test. 
  • Symptoms can impact any bodily system (more information below)

The following conditions are often associated with food sensitivities:

  • Irritable Bowel Syndrome (IBS)
  • Chronic Diarrhea
  • Cramping
  • Heartburn
  • Headaches
  • Migraine
  • Fibromyalgia
  • Muscle Pain
  • Joint Pain
  • Fatigue
  • Autism
  • Attention Deficit Disorder

How do you test for food sensitivities?

There are 2 main ways of testing for food sensitivities: blood or hair. The test provides you with reactivity levels to certain food components and usually tests 80-90 foods.  The most commonly used test looks at elevations in a specific  antibody, the IgG antibody. The LEAP/MRT test we offer, however, tests for multiple antibodies, not just one. 

Are all food sensitivity tests accurate?

All food sensitivity tests have some level of inaccuracy. This can vary based on gut inflammation,  if you have consumed the tested foods in the last 6 months, or potential cross reactivity with other food antigens. 

When it comes to accuracy, the IgG tests seem to have the most controversy surrounding them. As mentioned by the American Academy of Allergy, Asthma, and Immunology, “the presence of IgG is likely a normal response of the immune system to exposure to food. In fact, higher levels of IgG4 to foods may simply be associated with tolerance to those foods.” 

With that said, oral food challenges (eating the food and watching for symptoms) is the gold standard of identifying an adverse food reaction. This is time consuming and not always feasible for most, so the MRT test can provide you with a place to start. 

What is the food sensitivity test we offer?

It is called the LEAP/MRT test which stands for mediator release test. It is a blood test that measures reactivity level to 140 foods and 30 chemicals! With these results, your dietitian will create an elimination diet specific to you.  

What do results look like?

The MRT test will identify the foods that are non-reactive, moderately reactive, and highly reactive. These are taken into account when customizing the results to you.

mrt test food sensitivities

Example of LEAP results

View a MRT/LEAP Food Sensitivity Sample Report to get a sense of what foods and chemicals are tested, your results will completely unique to you.

shopping MRT Food Sensitivity Testing Tips

What happens after you get your results?

This is where the fun stuff starts! First, your dietitian/CLT will review the results with you and make the diet as manageable as possible based on your likes and dislikes! 

We start with your least reactive foods and add in foods one at a time to confirm they are safe for you. The end goal is to get you back to a varied diet, free from symptoms! 

How does a Certified LEAP Therapist (CLT) help through the process:

Working through your food sensitivities can be overwhelming!  Your CLT is your support during the whole process and helps break it down into manageable parts. Your dietitian will: 

  • Offer support throughout this overwhelming process.
  • Interpret the results with you and determine how best to implement the results.  Age, lifestyle, relationship with food, cooking ability and experience will all impact how the results are used.
  • Give recommendations on products and where to purchase them that fits within your LEAP diet.
  • Meal planning with phase appropriate foods.
  • Teach you new methods of meal prep and meal planning.
  • review food/symptom logs for links between foods and unwanted symptoms.
  • Incorporate other nutrition therapies for overlying conditions (SIBO (Small Intestinal Bacterial Overgrowth), lactose intolerance, fructose intolerance, food allergies etc.)
  • Access to LEAP mentor and CLT community for ideas to further support you!

When will you feel better?

Obviously, no promises can be made, but most people will see a drastic improvement in their symptoms in the first 7 days of the elimination diet. Long standing issues with food sensitivities or conditions like fibromyalgia/migraines may take more time to see complete symptom improvement such as 14-21 days. If there is no improvement at all in the first 7-10 days, your CLT will have to troubleshoot your food diary and any confounding factors such as medications.

Do I have to avoid these foods forever?

The simplest answer is not necessarily! It is unlikely ALL of your yellow and red reactive foods will cause problems. Clients usually end up tolerating the majority of the foods when tried, but may have a select few that continue to cause symptoms. What does this mean for you? If you continue to react to a food, then you should avoid it until your immune system calms down and retry it again later. Tolerance can change over time!

How can I get started?

Symptom relief is just around the corner! Here is what you need to do if you’re interested in testing: 

  1. Meet with one of our gut health dietitians to evaluate if this testing is a good option for you! We offer virtual appointments, so you can see an RD from the comfort of your own home. 
  2. The dietitian will order the test for you, and send you information on where to get your blood drawn. 
  3. Once you get your results back, your dietitian will go over everything with you and help you implement your results into actionable steps. 
  4. Follow-up nutrition counseling sessions in the office or virtual (review of results and guidelines, meal and menu planning, grocery shopping, eating out).


Blog updated June 2022

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As a certified LEAP therapist, Dietitian Kathleen can help you solve your digestive difficulties with cutting edge research and state of the art protocols. Co-author of Cooking with Food Sensitivities Survival Guide.