Food allergies common, growing, study says

Millions highly allergic to peanuts, milk, eggs and shellfish

October 19, 2010|By Meredith Cohn, The Baltimore Sun

A major new study bolsters the view that food allergies are among the nation's most common medical conditions, and researchers at the Johns Hopkins University and elsewhere believe the problem is growing.

The newly released study, perhaps the largest study of food allergies, showed that about 7.5 million people, or almost three in 100 people in the U.S., have a potentially life-threatening allergy to peanuts, dairy, eggs or shellfish. Children, as well as men and African-Americans, have higher rates.

"Food allergies are very real," said Dr. Robert Wood, director of pediatric allergy and immunology for Hopkins Children's Hospital and an investigator on the multicenter study. "It's among the most common chronic diseases in America. Food allergy has the real potential to cause dangerous or deadly reactions, so there needs to be more study and education."

The research, sponsored by the National Institutes of Health and conducted at Hopkins, among other institutions, was conducted to confirm earlier, smaller studies that have raised questions about the number of people sickened by what they eat.

The study was a conservative estimate, Wood said. It counted only those with severe allergies to four foods. It didn't count those allergic to other foods or with less severe allergies, or, more commonly, those who have digestive problems because they are intolerant to foods — meaning many millions more than those identified in this study must restrict their diets, sometimes in extreme ways.

Wood said that those highly allergic might have a dangerous reaction to a hamburger that was cooked on a grill at a fast-food restaurant where a cheeseburger had been cooked an hour before.

In the study, the most common allergy was to peanuts, with about 1.5 percent of people testing highly positive for the antibodies, proteins made by the immune system when faced with the allergens. About 1 percent were allergic to shrimp, 0.4 percent were allergic to eggs and 0.2 percent were allergic to milk. About 1.3 percent were allergic to more than one food.

Jake Meyrowitz is one of those allergic to milk. He's been allergic since birth, according to his mother Jessica Meyrowitz. The Bethesda mother had been supplementing breast milk with dairy-based formula and noticed he had a constant rash and gas and was rubbing his face on her as if he was itchy. Doctors came up with alternative theories, but Meyrowitz said she knew they weren't right.

She switched to soy formula and noticed a huge difference. An allergist tested Jake and confirmed the allergy. Later Meyrowitz would find out that he was also allergic to eggs, though now at age 8, he has mostly outgrown that.

Eliminating dairy and eggs from the household was no small task in the beginning, before labeling laws required manufacturers to list foods their products contain or may come in contact with. It was also before more people became aware of common food allergies, before peanut-free schools and before groceries carried foods designed for those with allergies as a matter of routine.

"It wasn't talked about eight years ago," Meyrowitz said. "Now I know tons of moms whose kids have allergies. ... This study confirmed what I already knew, and I'm not surprised. I think there may be more allergies, but really I think people just didn't know about it before, or they dismissed it."

Meyrowitz still has to control the food the family has in the house and everything Jake consumes, but it's more of a routine now. She's sure no one is missing out on anything. And she believes the whole family is more healthful because they eat fewer processed foods.

And as for milk, for the past year and a half Jake has participated in a study at Hopkins to try to treat the allergy with increasingly higher doses of milk protein to retrain his immune system. Meyrowitz said it's helping, and she worries less about Jake coming in contact with small amounts of milk.

Wood said there are several studies working on such treatments.

This latest research, published this month in the Journal of Allergy and Clinical Immunology, will be repeated in a few years to see if the prevalence of allergy is still rising, Wood said; past studies suggest it is. This study was based on blood samples and interviews with more than 8,200 people. They were ages 1 to older than 60 and participated in a large national study of various health matters by the NIH.

The study also confirmed links to asthma, eczema and hay fever. The food allergy, which generally surfaces in youth, likely precedes the other maladies and causes them, researchers said. The study also found higher prevalence in children, which is usually when the allergies develop. Kids can outgrow milk and egg allergies but don't usually outgrow peanut and shellfish allergies.

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