Food Allergy FAQ

By Sarah Daubman, RD
Staff Dietician

What exactly is a food allergy?

A true food allergy involves an immune system response from the body. The body identifies an offending food as harmful and releases antibodies to attack it. This triggers the release of histamine, thus precipitating the outward symptoms of an allergic reaction. These may include itching in or around the mouth, hives, nausea, stomach pain, difficulty breathing and/or anaphylaxis. Most often, people need to ingest the food for the allergic reaction to occur, but certain sensitive individuals may develop symptoms from touching the food or inhaling steam from which the food is being prepared (as in cooking shellfish).

How is that different from food intolerance?

Like a food allergy, a food intolerance is also an adverse reaction to food, but the body’s immune system is not involved. Lactose intolerance, for example, is when the body lacks the enzyme lactase needed to digest lactose, the sugar found in milk. Without the enzyme present, lactose remains undigested and ferments in the gut, resulting in gastrointestinal (GI) symptoms such as diarrhea, bloating or constipation. Lactose intolerance is therefore not the same as a milk allergy, which would involve the type of allergic reaction described above. The cause of other food intolerances may not be as easily identified but may trigger similar GI symptoms.

What are typical food allergies?

Unfortunately, any food can be a food allergy but eight foods account for more than 90 percent of them: egg, milk, wheat, soy, fish, shellfish, peanuts and tree nuts. Certain food allergies that appear in childhood may disappear as the child grows (milk, eggs, soy and wheat), but others (peanuts, fish and shellfish) typically never go away.

How are food allergies diagnosed?

Clinical testing for diagnosing a food allergy may include a skin prick test or blood testing. An elimination diet may also be recommended to assess whether removing the suspected food from the diet results in an alleviation of symptoms.

How are food allergies treated?

The only treatment for food allergies is to eliminate the food from the diet. In a case of multiple food allergies, a visit to a Registered Dietitian may be recommended to avoid any dietary deficiencies.


Where can I get more information?

About food allergies:
The Asthma and Allergy Foundation of America
www.aafa.org

The Food Allergy and Anaphylaxis Network
http://www.foodallergy.org/about.html

The American Pediatric Association
http://www.aap.org/healthtopics/asthma.cfm

To find a Registered Dietitian in your area:
www.eatright.org and click on “Find a Nutrition Professional” on the right hand side.