What’s the deal with all of these food sensitivity tests?



In the era of stressed importance on fitness and nutrition, people are taking notice of how various foods make them feel. We’ve heard it more and more when out to eat – “I have a food allergy” or “I have a food sensitivity,” but what’s the difference between food allergies and food sensitivities? How are they determined?

Both the least common and best-known example of food allergy is anaphylactic shock – a severe hyper-reaction of the immune system caused by a massive release of histamine and other immune mediators. This is certainly the most dangerous food allergy and it is a response to the body releasing Immunoglobulin E, or IgE. Food allergy affects about 1-2% of the population. The most common foods that trigger this anaphylactic reaction are peanuts, other nuts, shellfish, or foods containing sulfites. Anaphylactic reactions can be deadly within minutes if not treated immediately.

Food allergies can be diagnosed using a scratch test, in which small portions of suspected and/or likely allergens are placed onto skin that has been broken, or scratched. Within a relatively short period of time a rash will develop if an allergy is present, thus indicating a positive IgE reaction.  Blood testing of IgE can also be performed, and is considered more accurate than scratch testing.  This test is important when an anaphylactic reaction is suspected, but doesn’t evaluate for possible delayed food allergies.   

Food sensitivities are also known as delayed food allergies. Food sensitivities make a person feel sick because the immune system reacts to foods and causes chemical mediators to release from white blood cells. These mediators cause inflammation, pain, and other symptoms and can affect any organ system in the body. Further, these symptoms may not immediately manifest and may even present a couple of days afterward. Food sensitivities often go undiagnosed or misdiagnosed. The two most common ways to evaluate for food sensitivities is by either a blood test or an elimination diet.

An elimination diet is certainly the cheapest and most effective way to evaluate ones food sensitivities, however, it is also the most tedious. Common culprit foods are eliminated for a trial period of at least 3 weeks or until any chronic symptoms have resolved. Then, each eliminated food is reintroduced in a stepwise manner. The alternative is a simple blood draw that evaluates either immunoglobulins or immune system endpoints, or mediators. The blood tests are often not cheap, but for some people the convenience is more the worth it.

The food allergy scratch test is surely a unique test, but for sensitivities it best to ask yourself which suits you better – would a temporary diet be most effective or would you prefer to have answers in a shorter timeframe?

Dr. Brian Myers is a naturopathic primary care doctor with a focus on pediatric and family health at Live Well Clinic in La Quinta. For more information visit www.livewellclinic.org or call 760-771-5970.

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