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Food Allergies: 5 Myths Debunked

How to tell a food allergy from an intolerance or sensitivity -- and what to do about it.
By Katrina Woznicki
WebMD Feature
Reviewed by Laura J. Martin, MD

Nearly a third of people living in the U.S. believe they have a food allergy, according to a recent study published in The Journal of the American Medical Association . But only 5% of children and 4% of teens and adults have true food allergies.

Why do many people think they have a food allergy when they don't?

Experts say it’s because people don’t understand what really constitutes a food allergy and they often misuse the term.

“Unfortunately, the term ‘allergy’ is sometimes used by the public or health care providers to describe any unpleasant experience patients have with eating food, including ‘feeling bad,’” says Marc Riedl, MD, MS. He worked on the study in The Journal of the American Medical Association and is an assistant professor of medicine at the University of California at Los Angeles David Geffen School of Medicine.

Linking ‘food allergy’ with ‘feeling bad’ causes confusion, and can lead to people cutting out certain foods thinking they're allergic to them, when instead they may be missing out on delicious foods or risking nutritional deficiencies.

The National Institute of Allergy and Infectious Diseases, which funded the study, has released new guidelines about definition, diagnosis, and management of food allergies. 

Myth: I'm allergic to foods that don't agree with me.

Not necessarily.  A food allergy is a very specific  immune system response involving either the immunoglobulin E (IgE) antibody or T-cells. Both are immune system cells that react to a particular food protein, such as milk protein.

An IgE reaction occurs within minutes to an hour or so of either smelling, touching, or ingesting a particular food. The presence of the food triggers the immune system to over-react and interpret the food as harmful. Histamine is released, causing symptoms that range from mild to severe, including hives, itching, trouble breathing, wheezing, and anaphylaxis.

About 30,000 Americans per year go to the emergency room due to severe allergic reactions to food, and as many as 200 die every year from food allergies, according to the Food Allergy and Anaphylaxis Network.

A non-IgE immune system reaction can occur within three to four hours of ingestion and can often be mistaken for food insensitivity or food poisoning, explains Wesley Burks, MD, division chief of pediatric allergy and immunology at Duke University Medical Center in Durham, N.C.

“The biggest misunderstanding is that there are different types of food allergies, they’re reproducible, the reactions are the same,” Burks says. “You can’t eat cheese, feel sick, and claim a food allergy, but then turn around and enjoy ice cream and feel OK. With a true food allergy, the trigger does not change and the trigger will always set off the same immune system response.”

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