Food Allergies

Food Allergies

When Your Body Just Says No

It's one thing to make rules for yourself about food. It's another to have your body make them for you.

But that's what happens to women who have a food allergy or food intolerance, two health problems that are often mistaken for one another.

With both conditions, the body decides that certain foods should be off-limits. Through hives, rashes and a variety of other physical reactions, your body suddenly says "Nope. Can't handle that food. Time to give it up." And eating goes from being pleasurable to being problematic.

While it can be easy to confuse food intolerance and food allergy, there are important distinctions between them. While food allergy involves the immune system, food intolerance is generally a digestive problem. And while some symptoms of both disorders resemble each other, others do not.

The Allergy Label

Food allergy is often what people think they have when they have trouble with a particular food. Some folks truly do have an allergy. Researchers don't really know for sure how many Americans, let alone how many women, have food allergies, but estimates are that about 35 million people, or between 1 and 2 percent of the population, are affected. Others have allergy-like symptoms that are caused by something other than an allergy.

Research indicates that the public's perception of food allergies is actually quite different from reality, says Daryl Altman, M.D., an allergist and immunologist and director of Allergy Information Services, an allergy consulting service in Lynbrook, New York. In a study, Dr. Altman and her colleagues found that 13.9 percent of 3,700 U.S. households reported that at least one person in the household had a food allergy.

Anatomy of an Allergy

When you develop a food allergy, there's an actual shift in the functioning of your immune system. Your body starts treating food like the enemy. The immune system, designed to fight off foreign invaders like bacteria, starts attacking different types of food proteins. Researchers aren't sure why or how, but somehow the body starts to see what would normally be innocent, nutritious elements as harmful. "It treats it like an invader," says Michael McCann, M.D., a clinical allergist and immunologist at Kaiser Permanente Medical Center in Parma, Ohio.

When an allergic person is exposed to an offending food, the body produces a series of chemical reactions that result in the release of histamine. Histamine in turn causes many of the physical symptoms of allergy--itching, hives, runny nose or watery eyes. While food allergy can start off mildly, in some people it has the potential to progress into a more severe reaction called anaphylaxis, a life-threatening condition in which the throat swells and closes, blood pressure drops and the body goes into shock.

With food intolerance, there is no shift in the immune system. Instead, a number of things can be happening. Sometimes you have trouble digesting and metabolizing food because certain enzymes are lacking or not functioning right, says Dr. Altman. Symptoms can vary, depending on the food, but you can experience stomach and intestinal problems. You may also experience intolerance to certain foods because of the nature of the foods themselves. Some contain vasoactive amines, natural chemicals that constrict the veins and arteries in the head, she says. When you eat these foods--coffee, chocolate and hard cheeses--the vasoactive amines provoke migraine headaches.

Name That Food

There is a range of foods that trigger allergies or intolerance. The most common food allergen is milk, says Rosemarie Bria, Ph.D., director of nutrition at Allerex, a Greenwich, Connecticut, company that advises food companies about adverse reactions to food.

There are at least 20 protein components in milk that can lead to the production of food-fighting IgE antibodies. Two of the proteins, casein and whey, are sometimes found in other foods, so it's important for individuals with milk allergy to check labels. Casein is found in some brands of tuna even though it's not always listed on the label, so if you have a life-threatening allergy, consider calling the company that makes the brand of tuna you like to ask about the ingredients.

Milk allergy can be confused with lactose intolerance, a digestive problem in which individuals experience discomfort from dairy products because they don't have the right amount of the digestive enzyme--lactase--to digest milk sugar, or lactose. While these individuals can drink milk supplemented with lactase, this enzyme-treated milk will not work if you have a milk allergy, says Dr. Bria.

Other common foods that trigger allergies are soy, eggs, wheat, nuts and seafood.

Chicken eggs contain several common allergens. The white of the egg generally causes more allergies than the yolk. Cashews, Brazil nuts, almonds, pecans, hickory nuts, pine nuts, pistachios, walnuts and hazelnuts have been found to cause anaphylactic reactions in some individuals. The food responsible for the most allergy-related deaths is peanuts, experts say.

Seafood can also cause allergy, including anaphylaxis. People may be allergic to mussels, snails, oysters, scallops, clams, squid, octopus, lobster, shrimp, crab and prawns. However, some studies have shown that some individuals who are allergic to fresh tuna or salmon are able to eat canned forms of those fish.

Wheat is another food that may cause allergy, and often this sensitivity goes hand-in-hand with an allergy to rye and barley.

Food Allergies and Our Bodies

Women with allergies are often worried that their children will inherit them, says Stephen Wasserman, M.D., professor of medicine at the University of California School of Medicine at San Diego.

Babies may be exposed to allergens in problem foods like eggs, peanuts, wheat and milk either in the womb or after birth, through breastfeeding. If a woman with allergies avoids such foods during pregnancy or while nursing, she can decrease her child's risk of food allergy, Dr. Wasserman says.

Some studies show that such a strategy is most useful from pregnancy through the first year of a child's life, says Dr. Wasserman. Pregnant or nursing moms who are avoiding calcium-rich dairy products, however, must take calcium supplements, he cautions.

Avoiding certain foods during pregnancy or breastfeeding is not necessary for all women, says Dr. Wasserman. But in highly allergic families--where either the mother, the father or both are allergic--it may be something to consider, he says. A pregnant woman considering this should consult with her doctor before deleting foods from her diet.

Living with Food Allergies

There's no way for women to prevent food allergies, says Dr. Altman. But there are effective ways to cope with them. Here's how.

Make it official. If you suspect that you have a food allergy, it's important to be diagnosed by a doctor, says Dr. Altman. If you have symptoms, don't assume it's a food allergy. For referral to an allergist, call the American Academy of Allergy and Immunology's Physician Referral and Information Line at 1-800-822-2762.

Get tested. Your allergist can test you to see if the physical discomfort you experience after eating certain foods is indeed food allergy, says Dr. Bria. The most accurate test is called the double-blind, placebo-controlled test. For this test, your doctor will instruct you not to eat the suspected foods for one to two weeks. Then she will have you eat samples of foods that contain the suspected foods and others that do not. She'll observe your reactions as the dose is increased.

Other tests that are used but are less accurate are blood tests, which measure certain antibodies in the blood, and skin-prick tests, which involve pricking the skin, exposing it to the suspected food and watching for a red, puffy reaction. For the most accurate diagnosis, ask your doctor for the double-blind, placebo-controlled test.

Work with a dietitian. If you have a diagnosed food allergy, work with a registered dietitian to figure out what to eat, says Dr. Altman. She'll help you replace the nutrients you give up when you stop eating some foods, she says.

Keep it simple. When you're dining out, try not to get too fancy. Stick to dishes in which you can easily identify the ingredients, says Dr. Altman. Steer clear of fancy sauces that might have hidden ingredients you're allergic to.

Be blunt. If you have a severe food allergy and you're eating out, be direct with the restaurant staff, says Dr. Altman. "You have to say, 'I am severely allergic to peanuts and if I eat even the slightest little bit of peanut, I can die,' " she says.

Use separate utensils. "If someone is severely allergic to a particular food, get a special set of utensils for that food," says Dr. Altman. Use the utensils with that food only and don't use them for other dishes. This will prevent the food from accidentally being transferred into foods that the allergic person might eat.

Also, don't be afraid to ask a restaurant to cook your meal in a pan separate from that being used to cook other people's meals, says Dr. Altman. This will prevent any traces of the food you're allergic to from accidentally getting on your plate.

Watch the fruits. If you've got latex allergy or suspect you might, be careful about eating bananas and avocados. Some individuals with latex allergy have also been found to be allergic to these foods.

Keep your medicine with you. If you've got a severe allergy that can throw you into anaphylactic shock, you should carry injectable adrenaline, called epinephrine (EpiPen), with you, says Dr. Altman. "It does not help if the medicine is at home," she says. The injectable adrenaline comes in pen-size units and is easy to carry. It's a good idea to get several of these prescription devices so that you can keep them in different purses and jackets and in your gym bag and briefcase.