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Food allergy is getting a lot of buzz lately. Put simply, a food allergy is an allergic response to the protein in a food. When you think food allergy, you may think of eating something that suddenly causes hives or shortness of breath, an anaphylactic response that sends you to the hospital. This type of reaction is a true food allergy called an IgE response and is classified as a hypersensitive severe immune reaction that may affect the respiratory tract or circulatory system. These food allergies are very serious, and you probably know which foods to avoid if this is you, as onset usually occurs during early childhood. The most common IgE allergies are nuts and shellfish. According to the Food Allergy & Anaphylaxis Network, only about 4% of the United States population has a true food allergy.

There is another type of food allergy that is more insidious and may take up to 72 hours to surface. This is a delayed food allergy and is technically a food intolerance, an IgG response, which refers to the IgG antibody, the largest circulating antibody in your system.

What happens in this situation is that the IgG antibody marks certain food particles as antigens, and when you eat these foods, the body mounts an inflammatory immune response and attack. There is quite a bit of confusion about food allergy, food intolerance and food sensitivity. Food allergy is IgE allergy and food intolerance or sensitivity is IgG. For the purposes of this article, I am referring to IgG food sensitivity as food allergy.

IgG food allergy symptoms include the following

  • gas, bloating
  • headache
  • eczema
  • rash
  • acne
  • heartburn
  • fatigue
  • diarrhea
  • hay fever symptoms (itchy, watery eyes, sneezing)
  • asthma
  • insomnia
  • brain fog
  • joint pain
  • IBS or Crohn’s

Some estimates say that up 80 percent of people have IgG food allergies. Many practitioners use food allergy testing in their practices to help determine which foods are problematic. By avoiding those foods, one may lose weight, heal leaky gut syndrome, improve IBS or Crohn’s, heal eczema, and just plain feel better, because the allergy response creates inflammation that can lead to weight gain, leaky gut, and a host of other problems. But is food allergy testing accurate?

Is Food Allergy Testing Helpful?

There are several different types of food allergy testing. The ones you’ll most frequently hear about are ALCAT and ELISA testing, both by blood. ALCAT needs a serum blood draw, but ELISA can be done by fingerprick bloodspot testing. The blood tests detect and measure the amount of allergen-specific antibodies in your blood, and both test for IgG food allergies.

When you come into contact with an allergy trigger, known as an allergen, your body makes antibodies against it. The ALCAT Test (Antigen Leukocyte Cellular Antibody Test ) identifies cellular reactions to over 350 foods, chemicals and herbs and is thought to be the most accurate. ELISA is an abbreviation for enzyme-linked immunosorbent assay and is thought to be less accurate. I’ve previously used ELISA testing in my practice, because as a nutritionist, I cannot order serum blood draws, and I do have access to ELISA bloodspot finger prick testing (though I believe you can now order ALCAT testing on directlabs.com). It is my opinion that the ELISA tests may not be very accurate. I have seen many come back completely clean when the person had a known adverse reaction to a food.

But this is where it gets confusing: even if you do not produce allergy-specific antibodies to a food, you may still react to that food. This is why I don’t believe food allergy testing to be a good choice in most cases. In my experience, one may not tolerate a food because the person cannot properly digest the food and/or the food creates inflammation. An example is not being able to tolerate FODMAP foods if one has IBS or SIBO. That’s where the situation gets muddy: the food intolerance may not show up on a test because there is no reaction to the protein, but the person may still experience an inflammatory reaction. In addition, IgG antibodies are found in both allergic and non-allergic people. Experts believe that the production of IgG antibodies is a normal response to eating food and that these tests are not helpful in diagnosing a food allergy (source: Food Allergy Initiative). This article claims that “there are no reliable and validated clinical tests for the diagnosis of food intolerance. While intolerances are non-immune by definition, IgG testing is actively promoted for diagnosis, and to guide management.”

The ALCAT food allergy test gives you a report of all the foods you react to: severe, moderate and mild category. For many, sometimes hundreds of foods can show up across these categories, and that can be very overwhelming. It’s recommended to avoid certain foods in rotation and for specific amounts of time, which, again, can be overwhelming. In my experience, my clients have stressed so much about sticking to their rotation and exclusion plan that they become afraid to eat, which is a damaging place to be mentally. I typically have them avoid the foods in the severe category only.

With that said, I have seen some positive outcomes from avoiding foods on food allergy testing– in the severe category typically. Avoiding these foods for at least six months allows the gut to heal and seems to reduce inflammation, which can heal chronic conditions. I’ve also seen incredible reversal of eczema and autoimmune conditions. Be aware also that foods that show up mean you may be reacting to those foods right now due to leaky gut. Once your gut heals, you may be able to tolerate those foods again. So don’t get discouraged thinking you’ll have to avoid 100 foods for the rest of your life. The test results are letting you know what you’re reacting to currently. That said, some of these reactions may be inborn allergies and some may be a result of leaky gut.

So where does that leave us? Most often, after analyzing a client’s food journals and his or her symptomology, I can determine which foods I think are problematic, and I’ll recommend a food allergy elimination diet. I often think that is more accurate (and a lot cheaper) than food allergy testing— simply avoiding the foods you think may be problematic, then reintroducing them one at a time after a month or so. If you react to a certain food, you may have an intolerance or you may not digest that food well, so avoid it for six months and try again. The most common culprits are gluten, dairy, eggs, soy, corn, nuts, and nightshades.

Long story short: I don’t typically recommend food allergy testing. It can be overwhelming and overly exclusionary to avoid scads of foods (those in the moderate and mild categories typically), and I have doubts about its accuracy. I’ll try the food allergy elimination route initially, and if symptoms and problems persist, I may then recommend testing, ALCAT or the kit I mention below, and have the person avoid the foods in the moderate and severe category.

There are cases when I’ve seen food allergy testing to be effective: When a person has a severe allergy to a random food (like onions or kale) that she or he consumes regularly. Eliminating that food reduces inflammation, symptoms subside, and the person feels better. As with everything in holistic healing, I take every case into consideration separately before making recommendations.

Want to try at-home food allergy testing? I use this lab, and you can order a kit for 96 foods yourself.

I’d like to hear from you. Have you had food allergy testing? What was your experience?


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