Food Allergies: How Worried Should You be?

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"Allergic Reactions to Nuts Are Dangerous to Millions" "Girl's Death Highlights Hidden Danger" "Nothing's Safe: Some Schools Ban Peanut Butter as Allergy Threat"
WITH HEADLINES LIKE THAT, it's hard to know what's real about food allergies and what's hype. On one hand, the concern seems overblown. After all, some 25 percent of American adults think they have a food allergy--but only 1 to 2 percent of them actually do.

On the other hand, 2 percent of the population amounts to 5.2 million Americans--no small number. And for some of them, food allergies can be terrifyingly real. The Food Allergy Network, a non-profit organization of consumers and healthcare professionals based in Fairfax, Virginia, estimates that as many as 125 people die each year from food allergy-related reactions.

That number may be growing. While there are no studies yet comparing the prevalence of food allergy today to, say, 20 years ago, doctors report diagnosing more patients with food allergies--and more children with documented food allergies are showing up in schools.

In a person with a severe food allergy, it takes only a miniscule amount of food to trigger a reaction. Scott Sicherer, MD, an allergist at the Mt. Sinai School of Medicine in New York City, cites what could happen in a plane as an example. "An airplane is an enclosed space," he says. "When 100 people open their bags of peanuts at one time, the dust gets airborne and circulates around the plane." Someone with a severe peanut allergy could react by inhaling those tiny particles--without ever touching the peanuts--and end up with symptoms similar to those that one might expect when someone allergic to cats is in a room with a feline.

Peanuts are the leading cause of severe food allergy reactions, but they're not the only one. According to the Food Allergy Network, eight foods cause 90 percent of all allergic reactions. Besides peanuts, these include tree nuts (such as almonds, cashews, pecans, and walnuts), fish, shellfish, eggs, milk, soy, and wheat.

Why are these foods so dangerous to some people? The answer lies in the immune system. "In a food allergy, the immune system is overactive--the body thinks a harmless food is harmful," says Anne Munoz-Furlong, director of the Food Allergy Network. In reaction to the "invader" (which is almost always the protein component of a food), the body releases a flood of the chemical messenger histamine, which in turn triggers the typical symptoms of an allergic reaction: tingling or swelling in the mouth and throat, hives, vomiting, stomach cramps, or diarrhea that can set in anywhere from two minutes to two hours after eating the food.

People who have underlying asthma are more likely to have severe reactions involving the lungs, in which breathing can be difficult or next to impossible. Extremely severe reactions can produce a condition termed anaphylactic shock, in which the breathing passages close up, blood pressure drops, and the person could lose consciousness and even die.

Fortunately, the vast majority of food allergies are not life-threatening. And although children are more likely to have food allergies than adults (6 to 8 percent of youngsters versus I to 2 percent of adults), childhood allergies to a number of foods--milk, eggs, wheat, and soy--are commonly outgrown. (A child allergic to peanuts, nuts, fish, or shellfish, however, rarely outgrows the allergy.)

Note that many people unnecessarily restrict their diets--or their children's diets--because of a suspected food allergy. But self-diagnosing an "allergy"-and then excluding a food or group of foods-can cause problems of its own. Children, especially, can suffer from vitamin or mineral deficits.

If you or your child reacts poorly to a certain food, see a doctor to find out why. Some people who don't have true food allergies may actually have some form of food intolerance--a condition that may cause many of the same symptoms as an allergy but has a different root cause. For example, lactose intolerance is brought about by a lack of the enzyme lactase, which digests the sugar in milk. Someone with lactose intolerance may be able to handle milk in different forms, like yogurt or ice cream, or in small amounts. "In a true food allergy," however, "there's no tolerance level," says Ms. Munoz-Furlong. Your body can't "learn" to adjust to the food.

Get the Right Food Allergy Test
Below are several ways in which a doctor might narrow down the cause of (or rule out entirely) a suspected food allergy:

History & Physical A doctor will record your symptoms and rule out other kinds of allergies, such as those to dust, mold, or pet dander.

Diet Diary You may be asked to keep a diary chronicling the foods you've eaten and any symptoms you experience.

Scratch or Prick Skin Test (PST) A drop of food extract is placed on the skin, and a thin scratch is made through the drop. If a hive-like swelling occurs, it means that your body has made antibodies to the food-and there's a possibility that you are allergic to it. A negative result, however, virtually excludes the possibility of an allergy.

Radioallergosorbent Test (RAST) This is a blood test used for people with a history of severe allergies who might react too strongly to the food extracts used in the scratch test.

Double Blind, Placebo-Controlled Challenge This is the only test that can "prove" food allergy (rather than prove a lack of one). It should only be conducted in a doctor's office where medico/help is available in case of a severe reaction. I small dose of the suspected allergy-causing food is disguised and given to the patient, along with look-alike doses of a "safe" food. Neither doctor nor patient knows which is which, so the reaction isn't influenced by outside factors.

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