Food sensitivity testing: such an attractive idea! Just test, remove foods, and radical health improvement, right?
Not so fast.
Food sensitivity testing is a very attractive idea. Some marketing will give you the impression that you can take this one test, eliminate your ‘positive’ foods, and have a life-changing health revolution. Unfortunately, that isn’t how it actually works for the vast majority of people.
I’ve run food sensitivity testing with many people over the years and I’ve tried a lot of the different labs. I’ve even earned a special credential in food sensitivity testing: CLT (Certified LEAP Therapist). I’ve learned that there is a lot of nuance around WHAT test is used, for WHO, WHEN, and HOW the treatment plan is implemented. Here I’ll share the most common myths (vs facts) that I see regarding food sensitivity testing.
First of all, what are food sensitivities? They are an immune reaction to food proteins. So, if you’re lactose intolerant, for example, that’s an intolerance (you can’t digest that type of carbohdyrate), NOT a protein-related problem that involves your immune system.
Food sensitivities usually cause symptoms BEYOND digestive problems: things like fatigue, brain fog, headaches, joint pain, skin problems, stuffy nose, watery eyes, and/or mood changes.
How to test for them? The gold standard is the elimination diet (not actually a test). You take foods out, measure a change, then bring them back and re-measure a change. However, you can get a head start on that with a food sensitivity test that looks at antibodies or at cytokine release when cells are exposed to antigens (food proteins).
I’ve been running food sensitivity for years as a CLT (certified leap therapist) authorized to order the MRT test. However, I’ve really been doing a deep dive on food sensitivity testing this year. I’ve been reading books, journal articles, and even meeting with the world’s top labs to discuss their methodology. I also ran two different tests on myself the same day so that I could compare the results. You can grab by Cyrex Array 10-90 and Vibrant Wellness Food Sensitivity 1 + 2 Here:
I’ve come to the conclusion that food sensitivity is a great screening for intestinal permeability or leaky gut. It also can help me guide an elimination diet. However, it’s not as simple as testing and taking out food. There are a lot of myths and challenges that are important to understand:
1. Myth: I had allergy testing so I’m good.
Allergy testing looks at IgE-mediated antibodies. Food sensitivity looks at other types of immune-mediated food reactions (i.e. IgM, IgG, and/or IgA). So, food sensitivities are looking at non-allergy food reactions that still involve the immune system. They are usually more subtle than allergies.
2. I saw a cheap test on Instagram – let’s solve my health problems right now!
Food sensitivity testing isn’t simple, and the quality of the test is everything. For example, a quality test will have different reference ranges for each food. It will test the raw vs cooked versions of foods as appropriate. It will include enough foods to be useful (without missing tons of sensitivities). It will also run split testing to ensure an accurate result. Finally, a quality test will use quality proteins (i.e. pure and properly prepared) for testing. I also prefer to use tests that include non-food proteins such as food chemicals (dyes, meat glue, preservatives, gums, etc).
3. I can totally do this myself – why work with a pro? Just test and stop eating the foods!
It’s not that simple with food sensitivity testing. There’s actually quite a bit of controversy around whether it’s valid. For example, IgG antibody testing is the most common type and people have higher levels of IgG when food allergies improve with therapy! So, high IgG could merely by a sign that you eat that food often, not that you’re sensitive to it.
I think of testing primarily as a way to screen for intestinal permeability, then to reduce inflammation in the short term while we work on improving gut health and nutritional status. That work of addressing the root cause is critical. I actually had someone this week who had a food sensitivity test that came back with a lot of highs. Then, she took out those food for a few months then took another test. The second test showed her sensitive to all the foods she was eating to avoid her first sensitivities! So, you’re chasing your tail if you just take foods out without addressing the root cause.
Another challenge is that there can be non-immune reactions to food. If you suddenly change your diet to avoid your food sensitivities, you will be eating more of foods you don’t usually eat. Those might be foods that don’t sit well with you. For example, FODMAPs are types of carbohydrates that trigger digestive problems. Often, people who are sensitive to FODMAPs will naturally avoid them. However, a food sensitivity test can make these people start eating more FODMAPs (because their usual foods come back positive on the test). I learned about this problem the hard way. The first food sensitivity patient I ever had struggled with digestive problems. We dramatically changed her diet to avoid her positive foods, but her new diet was higher in FODMAPs. She was miserable! We changed her plan to avoid her positive foods AND FODMAPs, and all was good after that.
4. Myth: positive foods mean I’m sensitive to this food
Remember: people who improve food allergies with immune therapy have MORE IgG to that food. So, IgG can be considered a marker for oral tolerance, not sensitivity in every case. As an illustration of this, I’ll share the results from two food sensitivity tests that I got on the same day. One was from Cyrex Labs and the other was from Vibrant America. I also run MRT testing from Oxford but that is a different methodology. These two tests are IgG and IgA antibodies. What I was trying to do here is determine 1. If they matched and 2. Which lab more closely matches my experience?
You can download the two reports here:
Bottom line, I had higher IgG for foods I eat often but did not notice a difference when I took them out. So, it appears that I had good oral tolerance or ‘knowledge’ of these foods in my immune system.
Remember, though, that these tests are really useful as a screen for intestinal permeability. For example, anther provider in my clinic also did this split testing at the same time. He had a huge number of positive foods! I only had a few. So, right there, we’re seeing a big difference in intestinal permeability and immune reactivity. That knowledge might be more of the benefit than seeing the positive foods themselves.
Curious to hear more? Check out my podcast episode where I describe my test results in detail, plus share my interpretation of them:
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