A food allergy is an abnormal response of the immune system that is caused by the protein in certain foods. A food allergy is not the same as food intolerance. A person with food intolerance may have symptoms, such as abdominal distress, after eating a certain food. However, this response is not caused by the immune system.

What is going on in the body?

A food allergy occurs when an immune response occurs. An immune response is a normal response of the body to something it sees as abnormal. Usually the response is to bacteria, viruses, and toxins. Sometimes the body will recognize certain foods as abnormal. When foods are recognized as abnormal, the body produces an antibody known as IgE. IgE reacts with mast cells, which are part of the immune system. The reaction affects mast cells in many areas of the body, including the following:

When the IgE reacts with the mast cells, histamine is produced. This chemical produces the symptoms of a food allergy.

What are the causes and risks of the condition?

A food allergy is an abnormal immune system response to protein in certain foods. Following are some of the foods that commonly cause food allergies:

There is some evidence that genetically modified corn, known as StarLink, may cause severe allergic responses. This possibility is currently being investigated. Most people with food allergies also have other allergy-related disorders. These include nasal allergies to dust and pollen, eczema, and asthma.