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June 7, 2007

A listener asks: Why do we have allergies?


The why of allergies. I’m Bob Hirshon and this is Science Update.

Listener Carlie of St. George, Utah, called to ask:

Why do people have allergies?

We turned to allergist Donald Leung of the National Jewish Medical and Research Center in Denver. He says an allergy is your body reacting to something harmless as if it were dangerous. It’s probably the dysfunctional legacy of an immune response that was once effective at ridding our distant ancestors of parasites.

DONALD LEUNG (National Jewish Medical and Research Center):
It might still be very effective if you’re living in Africa or Egypt. But it’s not of great help to us because we don’t have many parasites here in the US.

He says how allergic you are and what you’re allergic to seems to be determined by more than 30 genes.

If you’re itching to ask a science question, call us at 1-800-why-isit. If we use it, you’ll win a Science Update mug. I’m Bob Hirshon, for AAAS, the science society.