What is a Food Sensitivity?

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Last updated: February 5, 2026

Created by: Kristen Carli, Dietetic Intern

Food Allergies, Intolerances, & Sensitivities

Food allergies are usually caused by a certain protein within the food. The 9 most common food allergens are wheat, soy, milk, peanuts, tree nuts, shellfish, fish, sesame, and eggs. Allergies cause a histamine response in the individual. When presented with an allergen, the body sends antibodies, made in response to the particular allergen protein, to fight the attack. This rush of antibodies throughout the body can result in various symptoms such as skin rashes or breathing problems.

Food intolerances don’t trigger an immune system response, but instead are caused by trouble during digestion. Food is broken down into smaller absorbable compounds by various enzymes. If one lacks certain enzymes, one may have a difficult time digesting and breaking down certain foods. This can cause uncomfortable symptoms like gas, nausea, and upset stomach. Lactose intolerance is fairly common. Those with lactose intolerance lack the enzyme lactase that is required to break down lactose, resulting in abdominal pain and gas symptoms after consumption of lactose-containing foods. A simple solution for these people is to consume lactase (sold in pill form) along with lactose-containing foods, or avoid lactose altogether. 

Food sensitivities are not a medical diagnosis. The term does not have a standard medical definition and is often used to describe allergies, intolerances or sensitivities.

Food Sensitivity Tests

Often, food sensitivity blood tests are not covered by insurance. Evidence is lacking on the efficacy of these tests in diagnosing adverse reactions to foods. Typically, these tests look for the presence of IgG antibodies. These antibodies have not been shown to reliably identify food sensitivities. In most people, IgG antibodies are present after eating food. 

Certain Foods Causing Health Problems?

If you suspect that certain foods are causing health problems, see your primary care provider and explain your symptoms. Your primary care provider can provide a referral to an allergist or registered dietitian. Contact AZ Dietitians today and our registered dietitians can develop an eating plan based on your triggering foods, health needs, and food preferences. 

Material adapted from eatright.org

Written By: AZ Dietitians
Published: October 28, 2019

Last updated: February 5, 2026

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