Five Reasons to Disregard Food Sensitivity Tests - Dietetic Directions - Dietitian and Nutritionist in Kitchener/Waterloo
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Five Reasons to Disregard Food Sensitivity Tests

5 Reasons to Disregard Food Sensitivity Tests

Five Reasons to Disregard Food Sensitivity Tests

For the past four years, I have wanted to request CBC Marketplace do an expose on the increasingly popular, “food sensitivity tests”.  These blood tests cost around $500-$700 and screen over 250 different foods to determine which foods you are “sensitive” to.  Awareness needs to be raised as millions of well-intentioned consumers are being swindled by claims that “hidden food sensitivities”, once eliminated, will “supposedly” rid our bodies of various health ailments such as digestive disorders, headaches, chronic pain and even weight issues.

Today, I will highlight my top five concerns with these pseudoscience food tests and why they should be disregarded.  Please share this blog with your friends and family and reach out to Marketplace to request the same segment!

Before jumping in, it is vital that we first make something very clear: food allergies are NOT the same thing as food intolerances!  You may be lactose intolerant but this does not mean that you have a milk allergy.

Food Allergy

Food Intolerance

Definition Immune- system response that can be fatal. Not immune-related; broad term to describe foods that your body has a difficult time tolerating at varying amounts.
Examples Peanut, milk, egg allergy, etc. Lactose Intolerance should limit their lactose intake.

Those with digestive concerns might like to try a dietitian-assisted Low FODMAP diet.

Diagnosis An allergist (Clinical immunologist, medical doctor) will take a medical history and perform skin test for IgE antibodies. No blood test is validated for diagnosis of food intolerance.

May use food-symptom diary, elimination diet, or breath hydrogen tests for lactose intolerance.




Five Reasons to Disregard Food Sensitivity Tests:


Find out my top five concerns with these food sensitivity tests and why they should be disregarded Click To Tweet


1.  IgG Test Lack Clinical Validity:

When our bodies are exposed to foods, there are different antibodies (proteins made by the immune system) that get produced. There are a total of five different subclasses of antibodies and they have different functions and locations in the body.

If your body produces IgE antibodies to a certain food, you can have an allergic response. For example, if Joe has a peanut allergy, he would have IgE antibodies in response to peanut protein and immediate symptoms may include: hives, vomiting, wheezing or a sudden decrease in his blood pressure.  IgE food allergy tests are clinically validated for diagnosing food allergies. Not all food allergies are IgE mediated, but this gets more specific than the scope of this article.

However, food sensitivity tests look for a positive IgG antibody and classify this as a “food sensitivity.”  The problem is the IgG antibody is the most abundant antibody in the body and is not clinically validated for diagnosing food sensitivity!  In fact, countless studies have shown that IgG antibodies will be positive based on food exposure (here, here, here).  Therefore, there will be many “false” IgG positive results in response to foods you are already eating.  Having a positive IgG response to certain foods does not mean that your body is reacting negatively against this food, instead, it demonstrates tolerance.  For example, children with true food allergies (IgE mediated allergies) are more LIKELY to have a tolerance to foods where they have increasing IgG antibodies (here, here). Similarly, immunotherapy or giving small amounts of an allergen to build tolerance is associated with increasing IgG antibodies showing improved tolerance (here, here).

Check out the Canadian Society of Allergy and Clinical immunology review of IgG food sensitivity tests.


2. False Promises 

These test exploit consumer trust; without solid research (even on the manufacture’s websites) to back up their innumerable claims.  Well intentioned, health-conscious consumers can easily be misled into purchasing these pricey food sensitivity tests.  After all, they are trusting the people advising them – alternative health practitioners, gym sales-people and even some pharmacies have these kits.

Check out here how Elisa Biotechnologies promotes the health benefits and how Hemocode System indicate that if you are “intolerant” to certain foods and continue to eat them, you can develop conditions like headaches, chronic pain and digestive disorders, fibromyalgia, psoriasis, acne, diarrhea and constipation.  Here’s a consumer tip, when there is no research to support something, the company will often use testimonials or case studies in its place.

food sensitivity

3. Lack of Symptom Improvement


With all the time and money spent on these tests, you would at least hope that you’d feel better.  Nope! In this research study published in International Archives of Allergy and Immunology 62% of patients were IgG positive for a number of foods, mainly egg, milk, casein and wheat. However, none of the patients with IgG-positive testing showed adverse reactions, neither immediate nor delayed, to the corresponding food when tested in a blind, placebo-controlled trial.

Most of the time, people ate these foods without any tolerance concerns.  Remember that the IgG blood marker is positive because your body has built a tolerance to this food.  This research study also found no benefit for those with irritable bowel syndrome (IBS) using IgG tests.


4. Unnecessary Dietary Restriction

As a registered dietitian, I have seen many clients come in completely over-whelmed with their long list of “food sensitivities”.  They literally do not know what to eat and have eliminated a lot of healthy foods from their diets.  Similarly, many people who have had these tests have already stopped following them because of the high level of restriction and no change in how they feel.  The most concerning however, are the children and people with serious medical conditions (kidney failure, cancer treatment) who have their diets severely restricted based upon IgG tests.  These vulnerable people are susceptible to inadequate nutritional intake for healthy body functioning and managing existing health conditions.


5. Be Critical!


Health information and dietary advice is flying at consumers from all directions.  But not all of this information is true or science-based and not everyone is a trusted authority.  To avoid spending money on a blood test that will likely give you a 20-page list of “sensitivities”, speak with a trained medical professional when dealing with your health concerns.  Book a consultation with an allergist if you believe you have an allergy or intolerance.  Speak with a medical specialist for other health concerns.   If you are experiencing digestive concerns like abdominal pain, bloating and change in bowel movements you might have foods you are intolerant to and may benefit from working with a dietitian who specializes in digestive nutrition.  Working with a dietitian can help you discover foods of intolerance through an elimination and challenge process based on your symptoms.


My Marketplace Request:

  1. Send host into different alternative health clinics for a “food sensitivity” test; compare results and advice that is provided.  As a Dietitians of Canada Spokesperson, I would be more than happy to speak on camera as a health and nutrition expert.
  2. Have the host try to eliminate all IgG positive foods and explore possible nutrient deficiencies. Host can also comment on any difference in how she feels.  Explore how manageable this level of dietary restriction is for long-term sustainability.
  3. Have the blood test re-taken (at three or five clinics) after months of dietary restriction.


Bottom Line:

Marketplace, please do an expose on these food sensitivity tests to save consumers from wasting their money.  These blood tests are expensive, invalidated, unreliable  and are not to be used as a diagnosis tool. IgG antibodies are linked with food tolerance and unnecessary dietary restriction can place people at nutritional risk.  Additionally, consumers need to know that IgG antibodies tests are not a remedy for curing all health ailments.


  • Kathleen M

    Wow! This is incredible. I was approached by the gym asking if I wanted to find out my food sensitivities- I have to admit, I was intrigued. I didn’t have the time to and I certainly didn’t have time to do research into the merit of these tests too. I am aware now, I can see how there would be a long list of sensitivities using this unproven, insensitive blood marker. Wow! Ppl need to know this. Thanks got update dietetic directions!

    • Jan

      I agree Kathleen – I’d never use or recommend IgG testing. But, not all food sensitivity testing is created equal. Don’t throw out the baby with the bathwater. I’ve rarely had a client in 15 years that didn’t improve significantly doing an Elimination and Reintroduction diet using the MRT test and LEAP Diet Protocol. Most also reduce their medication requirements. All I’m doing in changing diets and getting people well when nothing else has worked. Nearly 1000 RDN, CLT colleagues use the MRT test +LEAP protocol with great success. Happy to talk privately, anytime, to those open to scientific discussion. If the RD isn’t positioned to work with physician referrals, other non-RD practitioners will. There is a great need for more RDNs working in this area, but study the literature and understand the relationships between food sensitivity and inflammation.

      • Andrea D’Ambrosio, RD

        Thanks for reading and commenting Jan! This blog is written specific to the tests that are done in Canada. We do not have the MRT and LEAP that some of our American Dietitian counterparts are trained in providing. I agree that it is definitely an interesting area for future research and study 🙂

        • Jan

          Enjoying the thread. I’ve loved this area of study (but not IgG)! And, the rewards of working with happy clients and RDs is great. Well, that and being able to work via telecommute. But, if you had some refractory clients, MRT testing IS available in most of Canada. I’d be happy to work with you, as your LEAP mentor or consider the approx 30 hour LEAP Therapist Training (Full disclosure – I’m a co-author) that really helps explain the differences between IgE allergy, non-Ige allergy and Food Intolerance.

      • Linda

        Can you tell me how the MRT test is different from the Alcat test? I know they were created by the same person but have different patents.

        • Jan

          Hi Linda,
          Hoping to play today, so sharing info so well said by a colleague, Amanda Austin on

          “Both tests are cell sizing tests.

          When the white blood cells release their chemical weapons, the
          physical size of the white blood cells change; they get smaller and more
          dense/compact as they release more and more weapons (kind of like a
          balloon leaking air).

          ALCAT measures this response in your blood by measuring the changes
          in the size of white blood cells as they pass through an aperture (an
          opening). Unfortunately for ALCAT, their technology can’t get an exact
          read on this shift in size because white blood cells aren’t perfectly
          shaped little balls; they’re kind of jelly-like, so the shape can
          change, which interferes with their readings. ALCAT also only measures
          each of the white blood cells once and it can’t reliably distinguish
          between white blood cells and other things floating around in the blood
          sample (like red cell debris and other artifacts), so there’s a lot of
          room for error.
          MRT, on the other hand, goes about things a little differently by
          measuring the changes in the solids to liquids ratios. Since white blood
          cells release liquidy weapons during a food sensitivity reaction and
          then shrink down in size, the amount of liquids in a blood sample would
          take up more space while the solids would take up less space (changing
          the ratio). The more the ratio changes, the stronger the reaction.”

          So, the results of alcat are “green” (all the same reactivity), but MRT is able to “quantify the results” so we can start a client on an elimination diet specific for them, gradually adding foods back in about 10 days, once client is significantly improved (our expectation). With alcat, you’re just supposed to stay on only green for 6 months!

          Most colleagues that I know that have worked with both, and fully understand the LEAP Diet protocol, use only MRT +LEAP.

          In a nutshell, layman terms, I like to say that alcat measures cell changes 2 dimensionally, whereas MRT is 3 dimensional. But, it’s also about understanding that there is NO test that is 100% accurate. And, MRT cannot measure/test for celiac or NCGS, IgE reactions, reactions to high-histamine foods, carbohydrate/fodmaps malabsorption or reactions to excess fiber. Thus, the LEAP training, and why I’m a LEAP mentor, is to help the clinician understand when these other reactions might be part of the entire puzzle, and modify/test accordingly.

          For example, if a client has symptom suggesting celiac disease, I’d surely rule that out before using MRT. If a client had new-onset diarrhea, bloating and gas with lactose intolerance, I’d not use MRT first, I’d suspect parasites and go down that road first. (New onset lactose intolerance should not be treated with lactose free diet for life – address the CAUSE, which may be giardia infection!)

          Love, love this work, by the way! It’s complex, challenging clinically, and so important to not use “just a test” but understanding the client’s role/start/gut health/lifestyle in all this. For example, a client that reacts highly to yeast, mushrooms and candida albicans on MRT is often sensitized due to mold/mildew in their environment – and they don’t get fully well until we address and treat the environmental mold source.

          LEAP study is a really good intro to integrative and functional medicine.

          • Andrea D’Ambrosio, RD

            Thank you Jan for sharing your experience with a different type of food sensitivity test.

        • Andrea D’Ambrosio, RD

          Thanks for reading Linda! Your question is different from the topic of this blog and Jan would be the expert in that area!

  • Lauren Bauman

    You give more than enough reasons and evidence why food sensitivity tests are wrong and dangerous, and I support an expose by a show such as Marketplace to reach as wide an audience as possible. And you also offer alternatives for people who do suffer from digestive problems — see a qualified professional. Excellent, well-researched blog!

  • Andrea D’Ambrosio, RD

    Thank you Lauren and Kathleen for reading and sharing your viewpoints! Let’s keep the conversation going and spread the word 🙂

  • Thank effing GOD somebody wrote this article – it was on my ‘to do’ list.

    Its fricking insanity. And all my clients who do them – of course it doesn’t work! The evidence is SO bad. like. horrific. Its embarrassing. You can’t quote a study, that quotes a study, that discusses the theory behind this and say that THAT qualifies as actionable, evidence based practice.

    As someone who practices in unusual food allergies and intolerances, IgG is the most ridiculous money-grab of them all. People are like ohhh of course I feel bad I eat that food all the time! And I’m like THATS BECAUSE YOU REACT MOST HEAVILY TO THE FOOD YOU EAT ALL THE TIME. I’ve never, ever, ever had a patient a) be able to stick to it long term and b) get any sort of feel-good results from it.

    Gah ok I will stop ranting.

  • Andrea Miller

    Well done! This would be a really great story for Marketplace. Keep us posted. I will share this with my clients. I see so many clients who have this testing done, then show up in my office because they have no idea what they can or cannot eat! They unnecessarily restrict their diets, their nutrition suffers (to say nothing of their mental health!), and they get no relief from whatever symptoms the test claims it will improve. More consumer education regarding this testing, would go a long way!

  • Andrea D’Ambrosio, RD

    Thank you Andrea Hardy and Andrea Miller for reading and commenting! I am glad you enjoyed the piece and let’s keep the momentum to get this exposed to the public on a larger scale!

  • Suzanne A

    Thank you for a fantastic explanation that provides readers with a profound message in a simple, easy to read but extremely well-researched fashion. I previously felt confident in my awareness of the food sensitivity tests claims, but your post has expanded my knowledge base and further solidified my beliefs in the sham of the ‘tests’. It is nice knowing that education and awareness is getting out there on this topic, so that people with good intentions don’t get swayed by the sales pitch. I am curious to see how Marketplace responds to your challenge! Definitely viewer worthy!

  • Nicole Osinga

    Amazing article Andrea! I have been meaning to write an article like this – I’m glad to see you wrote such a comprehensive review! I have encountered a number of clients myself who have had these tests done and I find they leave my clients stressed and distraught. Often by avoiding these foods from the sensitivity tests, my clients don’t actually see improvement in symptoms either. I will be sharing!

  • Andrea D’Ambrosio, RD

    Thanks Nicole and Suzanne for reading and sharing your views! Thanks as well for sharing the message 🙂

  • Vincci

    Great article, Andrea! I agree this would be a great piece for Marketplace. Nutrition is already confusing for many people, and these bogus tests only serve to give people unnecessary dietary restrictions, making healthy eating more difficult and overwhelming.

  • Andrea D’Ambrosio, RD

    Thanks Vincci! Let’s hope Marketplace finally explores this topic- it’s long over-due!

  • I cannot wait to share this article with clients and friends. Thank you so much for putting such amazing effort into researching this topic well and so clearly communicating. It is so necessary for the public to be well informed about the scientific evidence (or lack of) around certain health and nutrition issues. These test results only enhance people’s fear of food, and as a dietitian who is passionate about folks developing a healthy and joyful relationship with food, this is detrimental.

  • Andrea D’Ambrosio, RD

    Excellent! Thank you Casey! I’m so glad you enjoyed the piece.

  • Michelle Jaelin RD

    So good, Andrea. So important to expose these tests. You would be an excellent person for CBC Marketplace to connect with!

  • Wendy Busse

    Thanks for writing such a great article Andrea. You made many excellent points. Another really important point is that the technique for doing IgG testing is not standardized. When I researched this topic for an online continuing education course, I called several labs that sell IgG testing. Most of them e indicated that they use the “right” methods and the other laboratories are wrong. I’ve had a project simmering on the back burner for many years. This would be a fantastic topic for a MSc research project and may be eligible for CFDR funding. Part 1: draw about four vials of blood from one person and send them to four laboratories. Conduct statistical analysis to determine if how similar the results are (this would need to be done by a professional statistician). Part 2: Send blood from one person each week to the same lab for about four weeks. It would have to be determined if the person’s diet would be consistent or change (because as Andrea said, IgG often reflects foods commonly eaten). Further tests could be determined based on the results of the first two. If Marketplace is not interested, perhaps the results of a well conducted research study would prompt them (or other media outlets).

  • Andrea D’Ambrosio, RD

    Thanks Wendy and Michelle for reading and commenting! Let’s keep the conversation going 🙂

  • Maria

    Wonderful article Andrea. You make some excellent points and draw attention to a real scam in the world of health and nutrition. I really hope this gets ‘exposed’ on marketplace.

  • Clayvessel

    As a person who acquired asthma suddenly at 40 years old and has for the last fourteen years done everything under the sun to eliminate the symptomatic coughing, it wasn’t until I eliminated cow dairy and gluten from my diet that I’ve gotten the cough under control (after having a food sensitivity test). Believe me, I don’t like having to give up wheat and dairy (cheese!!) but the results are clear. Now that I’ve been off them for six months even the smallest amount will get me coughing again. Tonight I had a taco with a wheat tortilla because sometimes I just feel like it. I haven’t had any wheat or dairy all week and sure enough, one tortilla and I’m coughing. You can say it’s all anecdotal and talk about studies, but you won’t convince those of us who actually feel the beneficial results to elimination diets and the return of symptoms after a lapse in indulgence.

  • Andrea D’Ambrosio, RD

    Hi Clayvessel, thanks for sharing your experience! Food sensitivities are food intolerances legitimate and elimination and re-introduction is the gold standard for identifying these food tolerance concerns. The concern with IgG tests is the false positives based on foods people are already eating, which could mean for people with legitimate diary or wheat intolerances, would be IgG positive for them (because they are consuming them) and the results would show a host of other foods as well. These test sometimes identify foods that are in fact tolerance concerns but it is not with consistency or because of the scientific rigour or reliability of these tests.

  • Guest

    I really enjoyed reading this article Andrea. I would absolutely be interested in watching a Marketplace segment on this topic. Good luck in your pursuit!

  • Leah McGrath

    Hi, I really appreciate this article. I hope more dietitians read this …one of the key points Andrea makes is that these food sensitivity tests that show you are “reactive” to certain foods or that they are causing inflammation have absolutely NO science behind them, no peer-reviewed studies, no clinical trials…just a lot of anecdotes. I worry that these types of tests may be creating a whole other category of disordered eating habits.

  • Jessica Hess

    Thank you for writing this article. I believe you captured what every dietitian wants to say when someone brings another food sensitivity test into their office. My reaction is always sadness because these people are in a vulnerable place having many horrible symptoms from possible real food sensitivities but are given false hope with a $500 unvalidated test just to have us tell them they were silly to waste their money. The truth needs to be out there so people know what they’re purchasing.

  • Michael F. Hoffman

    These blood tests cost around $500-$700 and screen over 250 different foods to determine which foods you are “sensitive” to. Clearly this limited investigation only applies to IgG testing which I agree has no clinical utility, so it would be wise to eliminate references to “all these tests” since there are a number of tests to which none of this in the article applies.

    • Lori Langer

      Agree, Mike! To lump all tests that practitioners have used to treat food sensitivities together is absolutely absurd. It’s like saying motorcycles, cars, planes, and trains are exactly the same b/c all are used for transportation. Please, no more references to “those tests” when speaking of tests marketed to treat food sensitivities. They are vastly different,with perhaps most, but not all, making false claims. I hope dietitians and other medical practitioners will do their homework (read, ask questions and think) before making bombastic statements on social media about topics they know little or nothing about.

  • MDBritt

    This happened to me a few years ago. I did some “food sensitivity” tests at the recommendation of an “anti-aging” doctor and these came back as sensitive to eggs and milk: two foods that were at the very center of my diet. I tried two weeks off and then two weeks on to see if there was any difference. Given that I wasn’t having any problems to begin with, I was kind of interested to see if some magic was at hand. But, no. In fact, I felt listless and bloated stuffing myself with alternative “milks” and enough vegetables and grains to make up for the lack of eggs – especially in the gym. I suspected that the test simply identified antibodies that were plentiful due to the quantity of these foods, so I passed it off pretty quickly (that, and the group doing the testing struck me as having some pretty woo-ey ideas). So *thank you* for putting some evidence behind my intuitions!!

    • Andrea D’Ambrosio, RD

      Thanks MDBritt for reading and sharing your story 🙂

  • Naturopathic Doctor-Arizona

    Your assessment is incorrect. The condition Leaky gut has now been validated by research and IgG tests help to determine if this is present. IgG Testing is a measure of IgG produced as a result of a certain molecule being introduced to the blood. That said, how FAP are used in patient care is key. If one is not trained or qualified to diagnose and treat and use accordingly, then it would have little value. Food sensitivity testing is not so much about a reaction to an individual food, but rather the state of the GI tract and a measure of inflammation. If food avoidance is not also accompanied by individualized treatment to heal the gut, decrease inflammation, restore normal flora, etc, then no, just simply avoiding foods will not likely show a change in symptoms. I have treated countless patients and utilized FAP/IgG testing as a tool to help and the results are astounding-people do extremely well. More research is needed, but I don’t condone anyone claiming to be an expert on something and dismissing something that could help a lot of people. If anyone reading this has questions or thinks a FAP may be helpful to them, consult with a Naturopathic Doctor. Blessings.

    • Andrea D’Ambrosio, RD

      I appreciate your opinion and clinical experience, I am not familiar with the research that you are referring you. Could you please provide one randomized and controlled study for us to review. I think it would help our readers form an opinion.

  • shannon

    Thanks for writing this article Andrea. I found it to be very helpful and informative especially since I have struggled with food sensitivities all my life and taken many of these tests! It is sad how many people are misled and misinformed on these tests and pay so much for them. I’ve already sent your article to numerous people to get the word out 🙂

  • Mary

    Interesting article.

    In the end, I would have to respectfully disagree with your stance, and I have first-hand experience. Suddenly, at age 36 I developed a persistent illness that I couldn’t shake. After months of wondering what to do, I finally came across a food sensitivity test. Turns out that I developed an oat allergy, and oat was a major part of my diet. I was eating oat three, four, maybe even five times a week.

    Unfortunately, the test told me to get rid of oat from my diet (blah!) but I couldn’t believe how great I felt a few weeks later. I will forever be grateful that I did give a food sensitivity test a chance because it changed my life.