A food allergy is an unfavorable immune response that occurs within a few minutes to two hours after being exposed to the food. The most common food allergies include eggs, peanuts, tree nuts, fish, shellfish, wheat, milk and soy. When someone with an allergy is exposed to the allergen, the body reacts by releasing inflammatory mediators or chemicals that display internal and or external symptoms including abdominal pain, diarrhea, nausea, vomiting, hives, shortness of breath, tingling in the mouth, or swelling of the lips, throat or other areas of the body. In severe cases, being exposed to an allergen can be fatal.
How Is a Food Allergy Confirmed?
A qualified medical profession will utilize a combination of tools to diagnose a food allergy. They may use your medical history, a physical examination and a series of valid diagnostic tests that could include a skin prick test, blood test, oral food challenge or a trial elimination diet. With a blood test such as the allergen-specific IgE (immunoglobulin E) test, it looks for allergens -- food, pollen, latex, etc. Other tests such as IgG4 (immunoglobulin G4) and IgG (immunoglobulin G) have been used to diagnose food allergies. However, the IgG is not an identifiable marker or recognized diagnostic method for testing food allergies and is believed to be a marker for food tolerance not food intolerance. Along with IgG, the IgG4 is an unproven diagnostic tool for confirming food allergies.
Food intolerance is an adverse reaction to a food or food additive related to the digestive system, not the immune system. Food intolerances can vary from person to person and be triggered by sulfites, enzyme deficiencies (as is the case when someone is lactose intolerant), specific compounds in foods or beverages, and tyramine or histamines (taken from a protein component). When a person is unable to digest or break down food correctly, he or she may experience similar but milder symptoms compared to food allergies: nausea, vomiting, stomach discomfort, headaches, irritability, etc. Unlike food allergies, the symptoms may take longer to manifest.
How Is a Food Intolerance Confirmed?
Presently, there is no reliable or validated test to identify food intolerances. One of the best ways to identify what foods may be causing you discomfort is to create a food journal. Track the foods, symptoms and the timing of the offense. A dietitian or licensed medical professional may suggest an elimination diet to help pinpoint the problem.
Food sensitivities are not life threatening, but unwanted symptoms appear after consuming problematic foods such as rashes, GI symptoms, headaches, reflux and fatigue. It’s not known if food sensitivities arises from an immunological mediator, a biochemical or a physiological defect, however, a food sensitivity is not the same as a food allergy. The evidence supporting the validity of food sensitivity blood tests as it relates to the diagnosing is lacking.
Food allergy, food intolerance and food sensitivity are not interchangeable terms.
As adverse food reactions vary by the diagnosis, so will the type of testing. You should not self-diagnose. Be cognizant of potential food or beverage culprits and be sure to seek professional medical advice.
Written by: Nadine Brooks, Wellness Workdays Dietetic Intern. Learn more about Wellness Workdays and our wellness program offerings by downloading our brochure.
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2. Cleveland Clinic
3. Food Allergy Research & Education
4. Krause's Food & the Nutrition Care Process
5. U.S. News & World Report
6. Mayo Clinic
7. Medical News Today