What Is a Food Allergy?

A food allergy occurs when the body’s immune system sees a certain food as harmful and reacts by causing allergic symptoms. Foods that cause allergic reactions are allergens. There are different types of allergic reactions to foods:

  • Immunoglobulin E (IgE) mediated. The body’s immune system makes antibodies called immunoglobulin E (IgE). These IgE antibodies react with a certain food and cause symptoms. In the U.S., the most common causes of food allergy are these eight foods:
  • Non-IgE mediated. Other parts of the body’s immune system react to a certain food. This reaction causes symptoms, but does not involve an IgE antibody. Someone can have both IgE mediated and non-IgE mediated food allergies.

Not all people who react to a certain food have an allergy. They may have a food intolerance. Examples are lactose intolerance, gluten intolerance or sulfite sensitivity. Food intolerance does not involve the immune system.

Visit our food allergy division – Kids With Food Allergies:

  • Learn more about food allergies
  • Find allergy-friendly recipes
  • Connect with parents managing their children’s food allergies
  • Get information about managing food allergies in schools


Medical Review October 2015