Food Allergy Diagnosis – What is the Gold Standard? (And why is it rarely used?) by Emily Kennedy, MSc, RHN

by | Dec 20, 2016 | Blog, Nutrition | 0 comments

The Best Way to Identify Food Allergies


At Markham Integrative Medicine, patients – adult and pediatric – can opt for food allergy testing as effective strategy for reducing systemic inflammation, reducing toxic build-up in the gut and healing neurological and physiological symptoms that are linked to incomplete digestion of specific proteins.

The vast majority of those tested get positive results for some degree of sensitivity to at least one of the top 10 allergenic foods (peanuts, tree nuts, seafood, milk, eggs, soy, wheat, sesame seeds, sulfites, and mustard). Combine that with a need to eradicate the fungal activity (yeast) in many of these inflamed digestive tracts and well, – you can see how meal planning gets tricky.

If you are considering food allergy testing, good for you! Please recognize, however, that each method of diagnosis comes with limitations. The IgE/IgG blood test (ELISA) does not predict the severity of a symptom reaction. More importantly, there’s also a high probability of a false negative result from undetected circulating IgE antibodies, or a false positive from foods that are cross-reactive to the suspect food.

As Dr. Gannage explains, it is problematic in that elevated IgG levels are an adaptive response in a healthy way to antigens in the diet, indicating “tolerance” – and don’t necessarily reflect any harm or correlation with any disease state. A high number of reactive foods, however, indicates an issue with intestinal permeability, and a need to focus on healing the “leaky gut”.

Other common methods of food allergy diagnosis – the skin prick test, or more “alternative” methods like cytotoxic testing, Vega testing, applied kinesiology, and hair analysis – also come with significant limitations, considering that what a person can or cannot eat is at stake.

So how do you prevent false results and get an accurate diagnosis? The American Academy of Asthma, Allergy and Immunology recommends that additional investigations such a physician-supervised Oral Food Challenge be administered before making the final diagnosis. This is a double-blind procedure in which the patient ingests increasing amounts of both a control and allergenic food until symptoms occur. Can you picture it? What a time-consuming and costly process. However, it is the gold standard.

Back to the drawing board….how can you accurately – and cost-effectively – pinpoint the problematic foods in your diet?

In my opinion, a carefully planned Elimination Diet with diligent documentation of quantities, cooking methods and any symptoms, major or minor, is the best way to go. If you’ve already undergone blood work, then the diet can systematically focus on eliminating and re-introducing each of the allergenic foods the test has identified. It is a process, taking at least 3 to 6 weeks – but that’s nothing considering what’s at stake. Imagine never figuring out that you can actually eat eggs, or seafood, or fish!

One more thing. Diligent documentation of food intake and concurrent symptoms should be done in the weeks leading up to allergy blood work as well. That way the knowledgeable allergist can factor in your cooking methods, or your tendency to eat the same thing for breakfast everyday, when interpreting your results.

For training on how to document food intake and enhance the accuracy of your food allergy test results, or how to meal planning for nutritional completeness, variety and flavour after getting diagnosed, please consider enlisting the services of a registered nutritionist. It is a small investment considering what a large role food plays in our lives.

To schedule an appointment with Emily Kennedy, RHN, or any other practitioner at Markham Integrative Medicine, email; phone (905)294-2335; or complete the “book an appointment” form at

Learn more about working with Dr. Gannage