ear-wheat-cereals-grain-40514People are often confused by the terminology describing food allergies, sensitivities and intolerances. This confusion leads to miscommunication at the doctor’s office when requesting testing to see which foods are causing digestive issues. To better understand the types of immune reactions that occur, let’s look at how food allergies, sensitivities, and intolerances can show up in the immune system.  

Often people claim they have had food allergy testing but “nothing came up.” First, know that the word “allergy” refers to one very specific immune reaction, the IgE mediated response. “Ig” is the abbreviation for immunoglobulins or antibodies, which are the flags for the immune system stimulating reactions. IgE antibodies are the basis for the true allergic reaction in the body, when mast cells dump histamine and other inflammatory elements into the body, often causing runny noses, hives, watery eyes, diarrhea, or in extreme conditions, anaphylaxis. This extreme allergic reaction prompts the screening for such food triggers as peanut or egg and for environmental triggers such as a bee sting. EpiPens are usually prescribed for life-saving measures.

When a food allergy is tested, it is often only the IgE response that is assessed, this means that other immune reactions are often missed. However, the gastrointestinal reactions to food associated with diarrhea, gas, bloating, constipation, reflux, nausea, vomiting are not 100% comprised of the IgE responses. Two other main antibodies are involved – the IgG and IgA.

IgA is the main antibody found in mucous secretions of the gastrointestinal, urinary, and respiratory systems. At low levels, IgA is involved in the normal production of mucous, but when highly elevated, inflammatory reactions can occur. The triggers for Irritable bowel syndrome (IBS), asthma, and interstitial cystitis (IC) can be strongly associated with IgA-related food intolerances. Like the IgA reaction, IgG also involves disorders of the GI system and the lung. IgG, technically a hypersensitivity reaction, also plays major roles with autoimmune disorders such as Graves and Hashimotos, Lupus, Myasthenia gravis and inflammatory conditions involving the joints.

To understand how foods can contribute to inflammation in the body, a simple ELISA test can be ordered (Enzyme-Linked Serological Assay). ELISA testing screens antibodies and the protein sequence can be matched to the proteins in foods. These evaluations can guide an elimination diet to understand your symptom picture. The most common mistake with food sensitivity testing is not evaluating enough antibodies. IgA, IgG, and IgE are the minimal tests that should be ordered.

Also know that if you are certain of a symptom connected to a food reaction in your body, yet the food sensitivity test comes back showing no antibody response, this may indicate that another immune reaction is at play. All tests need to be interpreted with regard to your symptoms, which is why it is important to openly and honestly consider your reactions and food exposure with your healthcare provider.

It’s important to know that not all food allergy testing is created equal, and to know the antibodies being assessed. Ultimately, know your body and don’t fall into the trap of assuming food is not the trigger to inflammation. Food is the best medicine, but the wrong food is certainly the worst poison.  

For more on IBS and allergy testing, join Dr. Amy Nelson for her seminar “IBS: Gut Inflammation and You” on July 24.


Amy Nelson, ND, received her Naturopathic Doctorate from the National College of Natural Medicine in Portland, OR where she studied nutrition, homeopathy, herbal and functional medicine. In addition, Dr. Nelson was the Associate at The IBS Treatment Center in Santa Monica where she treated irritable bowel syndrome and complex food allergies. Dr. Nelson utilizes her experience in natural medicine to address female and male hormonal imbalances, mental health, and digestive disorders.