Confused about food sensitivity testing?

27/Mar/12 06:08 PM

by Kate Whimster, BCom, MIFHI, ND

This subject is covered in a past post What's the difference between food sensitivity, allergy, or intolerance?, but given the recent media attention on food sensitivity testing I wanted to provide a pro/con (in this case beginning with the “con” side) summary for anyone who might have questions. Then I’ll explain how I look at food sensitivities in my practice.

Question: Is there value to food sensitivity testing?

Con:
There has been a lot of media coverage in response to an article (unfortunately you need to be CMAJ member for full access) by Dr. Elana Lavine in the Canadian Medical Association Journal criticizing food sensitivity testing.

Here is an article from the Globe and Mail: Tests for food allergies, sensitivities a ‘waste of money,’ doctor says
And here is a video with a bit of a more balanced perspective from the CBC: Food sensitivity tests

Pro:
There are several counter-arguments to be made to Dr. Lavine’s assertions:

IgE testing (for food allergy) and IgG testing (for food sensitivities) are different things. For a great comparison, here is a presentation from Rocky Mountain Analytical, one provider of food sensitivity testing. For a good summary, check out the chart on slide 11.
A skin-prick test, while considered the gold standard “allergy” test, is not a method that tests your response to food in the way you are actually exposed to food. You don’t eat through your skin, you interact with food via your digestive tract. And the response that your body makes to food can be an IgE response (quick, itchy, clear cause and effect) or an IgG response (delayed, vague symptoms, difficult to identify cause).
Only a medical professional (naturopathic doctor ideally or a medical doctor well-versed in nutrition) can understand how to best administer the test to get the most useful results and use this information for effective treatment.

Contrary to what Dr. Lavine asserts, there is research evidence for the use of food sensitivity testing:

This article summarizes some research on IgG allergy testing
Food-specific serum IgG4 and IgE titers to common food antigens in irritable bowel syndrome
Diet restriction in migraine, based on IgG against foods: a clinical double-blind, randomised, cross-over trial
Serum IgG responses to food antigens in the italian population evaluated by highly sensitive and specific ELISA test
Specific humoral response to cows' milk proteins and ovalbumin in children with atopic dermatitis
Treating irritable bowel syndrome with a food elimination diet followed by food challenge and probiotics
A critical review of IgG immunoglobulins and food allergy implications in systemic health
I’m sure there is even more to be found - check out PubMed if you are interested.

Here is a good, succinct rebuttal from Dr. Elaine Chin and here is a press release from the Ontario Association of Naturopathic Doctors.

My thoughts:
In my practice, food sensitivity testing is not my first choice for treatment, but I have used it in certain circumstances. Here are some key points I consider:

The test measures only one point in time. Human beings, however, are constantly adapting and changing. At the time of testing, results indicate a particular response to foods. But how might these responses change as your immune system is balanced such that it does not react to substances that are not harmful? I see changes in immune response all the time, most commonly when I treat seasonal allergies. I’ve treated patients who have progressed from constant anti-histamine usage (that was still not controlling symptoms) one year to nearly no symptoms and no need for medication the next.
Nutrition is a major part of my treatment with most patients. My approach to nutrition is that there are no “bad” foods, just foods that work well for you (the patient) and others that don’t fuel your body in the best way to achieve optimal wellness. I look to personalized nutrition to identify what the best nutritional approach will be for each individual.
There are several health concerns that warrant investigation into food sensitivities, such as: most digestive concerns (IBS, constipation, diarrhea, acid reflux), asthma, migraines, chronic fatigue, fibromyalgia, allergy symptoms, skin issues (eczema, psoriasis, acne), arthritis), failure to thrive, and more. The question is, what is the best way to determine foods that may contribute to these conditions?
Before testing, I encourage patients to do an elimination diet, which is considered the gold standard for identifying foods that may be contributing to symptoms. This approach is both diagnosis and treatment at once: patients usually experience a significant reduction in symptoms while in the elimination phase (confirming that eliminated foods contribute), they immediately begin to alter habits (perhaps the most challenging aspects of naturopathic treatment), and they gain firsthand experience of how foods affect them during the reintroduction phase.
However, some patients prefer more objective information via a lab test and find this more motivating for changing habits. Also, some patients may find the elimination diet very challenging and would prefer a more focused elimination diet based on lab results. In either of these cases, it is important to use the test results as a guide and symptoms as feedback to determine if the treatment approach is effective.
In the case of gluten sensitivity, I also find lab results more motivating for patients, since 100% avoidance of gluten can be challenging and having “hard data” as well as other lab results to monitor (one example would be anti-thyroid antibodies) can help ensure higher compliance and therefore improved outcomes.

I hope this helps clarify some of the key issues! The bottom line is that you will receive the best outcomes via individual treatment with a naturopathic doctor who can determine what approach is best for you and then navigate that path with you to ensure treatment addresses your needs.

Tags: Food allergy, Food sensitivity, Acne, Eczema, IBS, Constipation, Diarrhea, Migraine, Gluten sensitivity