Can your diet during pregnancy and breastfeeding protect your baby from food allergies?

By Elissa Sonnenberg

It's estimated that food allergies up to 8 percent of children, says Scott H. Sicherer, MD, of the Jaffe Food Allergy Institute at Mount Sinai School of Medicine, in New York City. For these kids, eating certain foods triggers an immune system overreaction that can cause anything from chronic itching and eczema to sudden difficulty breathing and even life-threatening anaphylactic shock.

The problem is growing—the incidence of food allergies in children increased 18 percent from 1997 to 2007. Scientists aren't sure why, but theories include greater awareness among parents and doctors, lower immunity because of less exposure to bacteria, and lack of exposure to common allergens early in life. However, keep in mind that a true allergy is different from a more common food intolerance (also known as sensitivity) in that the latter typically triggers less serious problems, such as gas, bloating, or diarrhea

The Importance of Diagnosing Food Allergies

While young food-allergy sufferers number in the millions, Dr. Sicherer stresses the importance of securing a trustworthy diagnosis before drawing any dietary conclusions. Restricting a baby's diet without your pediatrician's guidance carries risks of its own. "The biggest danger is that you create a child who has a narrow range of food choices," says Frank Greer, MD, past chair of the American Academy of Pediatrics (AAP) committee on nutrition and professor of pediatrics at the University of Wisconsin Medical School, in Madison.

Eliminating a suspected food, which could be filled with important nutrients, from your child's diet before any allergy has been diagnosed is a misguided approach that can mask or trigger other health concerns, adds Amal H. Assa'ad, MD, a professor of pediatrics and director of Cincinnati Children's Hospital Medical Center's Food Allergy Clinic.

Food Allergy Symptoms

An itchy rash. Diarrhea. Upset stomach. Is it a virus, a food allergy, or something else? Knowing the difference can help you and your baby rest, and eat, easier.

In a food allergy, the immune system reacts to a harmless food as if it were a threat and creates histamines and antibodies to fight it. Symptoms range from a tingling in the mouth and swelling of the tongue and throat to difficulty breathing, hives, vomiting, abdominal cramps, diarrhea, and a potentially fatal drop in blood pressure or shock, known as anaphylaxis. Every exposure may increase the reaction's severity. (Intolerances, also called sensitivities, may cause diarrhea, but they're not allergies; they occur when the body has trouble digesting a certain food.)

Ninety percent of all food-allergic reactions are to peanuts, eggs, milk, shellfish, wheat, soy, fish, and tree nuts (such as almonds and walnuts). Fewer than 10 percent of kids with food allergies react to corn, strawberries, and citrus fruit. Because babies don't typically eat a wide range of foods, the most common allergies seen early on are to milk, eggs, and soy, notes Dr. Sicherer.

As their immune systems mature, most children outgrow allergies to egg and milk by the time they enter elementary school. Food allergies can be triggered at any age, even after a food has been ingested for years, but allergies to peanuts and different types of fish are typically the most life-threatening and often manifest themselves early and last for life.

Food Allergies and Genetics

"Eczema is one of the earliest markers of an allergic person," says Dr. Assa'ad. A family history of eczema, asthma, and allergies also raises the stakes. "You may inherit the susceptibility to become allergic. It's not anything that the mother does when she's pregnant or breastfeeding or anything that the father does," says Dr. Assa'ad. Some children just get a bigger share of the genes that predispose them to food allergies.

If your infant is diagnosed with asthma, eczema, or a food allergy, follow your doctor's instructions on the timing of solid foods, says Dr. Greer. If none of these conditions is present, then you don't have to wait to introduce any food once your infant begins solids between 4 and 6 months, he adds. (Of course, certain foods might also have to be restricted because of other health concerns or choking hazards.)

Preventing Food Allergies When Pregnant and Breastfeeding

In the past, conventional wisdom held that avoiding highly allergenic foods during pregnancy and breastfeeding and withholding them from a child during his early years could reduce his risk for food allergies. (These foods are wheat, soy, cow's milk, fish, shellfish, peanuts, tree nuts, and eggs.) But recent evidence has turned that advice upside down. Now it seems there may be no reason to say no to allergenic foods, particularly wheat, eggs and fish; in fact, avoiding them may actually increase your baby's risk of developing food allergies.

If you’re pregnant, it's OK to eat highly allergenic foods unless you are allergic to them. There is no proof that staying away from them lowers allergy risks in babies. In fact, cutting them from your diet may cause more harm than good, as most allergenic foods provide crucial nutrients for you and your baby. For example, omega-3 fatty acids in fish and shellfish promote fetal brain development, and the folate in peanuts helps prevent neural-tube defects, such as spina bifida.

What’s more, avoiding allergenic foods while breastfeeding has not been shown to provide any benefit to your baby. However, researchers do believe that breastfeeding itself may help ward off food allergies. "Exclusive breastfeeding—no formula—for four months or longer is the best thing," says Frank R. Greer, M.D., professor of pediatrics at the University of Wisconsin and co-author of an American Academy of Pediatrics clinical report on food allergies. If your breastfed baby reacts to something you eat, avoid it. As for the opposite tactic—going out of your way to eat allergenic foods during pregnancy or breastfeeding— there's no evidence that doing so offers any protection against allergies either, Greer says.

Smart Feeding Strategies

According to the American Academy of Pediatrics, offering your baby allergenic foods is OK starting at four to six months; just be sure to watch for any allergic reaction (symptoms include hives, itchy eyes or mouth, vomiting, pale skin, fainting, difficulty breathing and swelling of the eyes, tongue or lips). Not only does withholding these foods offer no protection, but a 2008 study found a tenfold greater chance of peanut allergies in children who did not eat foods containing peanuts during infancy and early childhood compared with those who did. "Introducing allergenic foods to your infant after four months while he's still being breastfed may also protect against the development of food allergy," Greer says.

In late 2007, Greer and the AAP's committee on nutrition revised the AAP's nutritional guidelines for babies with eczema or a family history of allergies.

  • Try to exclusively breastfeed your baby for at least four months, and don't restrict your own diet.

  • Choose formulas carefully if you must supplement. Dr. Greer suggests that parents not use formulas made from more common allergy triggers like cow's milk or soy. Instead, use hydrolyzed protein formulas. They contain predigested proteins, making them easier to digest. They're less likely to cause allergic reactions, says Dr. Greer.

  • Using "hypoallergenic" formulas that are made with hydrolyzed proteins may delay an allergy's onset, but the formula won't prevent it from occurring.

  • If your baby has eczema, delay solid foods until she is about 4 to 6 months old. She will get the nutrients she needs from breast milk, with the possible exception of iron, which she can take as a supplement. Your doctor may also suggest restricting her diet, such as waiting to introduce eggs until she is 2 years old.


Tips on Food Allergy Testing

If you suspect your child has a food allergy, preparation and planning is key to diagnosis and management.

Keep a food diary. As with any baby, irrespective of allergies, introduce new foods one at a time, two to three days apart. Record everything that your baby eats for several weeks as well as any related symptoms (eczema, fussiness, gas).

Talk to your pediatrician and visit an allergist. Although it may be tempting, don't diagnose your child's allergy. Establish good relationships with doctors you trust who can advise you.

Get your child tested. Your doctor may recommend a radioallergosorbent test (RAST) or a prick-skin test. RAST, the latest version of which is ImmunoCAP, is a blood test that measures levels of antibodies to specific food proteins. High levels of antibodies indicate a possible allergy. It can take anywhere from a few days to a week to get results from this very sensitive test; 50 to 60 percent of positive RAST results are false positives. In prick-skin tests, results are nearly immediate: Any food that causes a raised bump or hive is positive. Fifty to 60 percent of positive skin test results are also false positives.

"Both of the tests measure the same things," explains Dr. Assa'ad. "It's not like one test is better than another," she adds. "Go into an allergist's office, you're going to get the skin test; go into a pediatrician's office, you're going to get the blood test."

If personal histories are uncertain and preliminary tests are inconclusive – say your kid's prick-skin test registers a wheat allergy but her favorite snack is toast – she may need the most accurate test available. A food challenge, which medical staff must closely monitor, requires that the patient ingest gradually increasing amounts of an allergen and wait for a reaction.

Learn more. Dr. Assa'ad, who tests babies as young as 3 months to see if they tend to be allergic, points out that any test is only valid for that individual at a particular point in time. A child who has eaten peanut butter and jelly for years, for example, could one day have an allergic reaction to her once-favorite meal. On the other hand, my sons, who used to have an extreme reaction to eggs, now enjoy baked goods and other foods containing cooked eggs. To get a good handle on the developing immune system, Dr. Assa'ad suggests retesting your child every one or two years to confirm the continued presence of food allergies, especially as diagnostic tools improve.

Living Healthy, Living Safe

You can help ease the stress of living with food allergies – from daycares to family vacations – by being prepared.

Read food labels carefully. A peanut-allergic child, for example, can't eat plain M&Ms safely because they are processed on the same machinery as peanut M&Ms. (Beware of sunflower seeds as well; the manufacturer that produces them may sell peanuts too.)

Ask about flu shots. While the mumps-measles-rubella vaccine is cultured with egg, studies have shown that it is safe for children with egg allergies. However, the flu shot, also cultured in egg, may cause a reaction in rare instances. Discuss with your allergist whether the benefits outweigh the risks.

Make a plan. Determine the steps you need to take in case your child has an allergic reaction. Communicate your plan and any emergency precautions to caregivers, family members, and teachers, as well as your child. For example, mine is simple: First, administer epinephrine, such as EpiPen Jr.; second, call 911; third, call the parents.

The first few minutes of a reaction are critical – early treatment with epinephrine and/or a liquid antihistamine, such as Benadryl, saves lives. Because not every ambulance in every state carries epinephrine, it's best for both you and your caregiver or child's school to have a supply on hand.

Carry safe food and snacks with you at all times. Give them to daycare providers, babysitters, and friends who may watch your child.

With more research under way, potential for vaccines and other new food-allergy treatments keeps parents like me optimistic for the future.

The Top 8 Hidden Food Dangers

Experts estimate that these foods cause 90 percent of food-allergy reactions.

Federal labeling laws require manufacturers to more clearly identify ingredients associated with the top eight food allergens. The Food Allergy and Anaphylaxis Network provides ingredient-reading cards that list unusual names and food sources for these allergens. Here's a sampling.

Allergen: Egg

Alternate Names: Albumin, lysozyme, globulin, ovumucin, vitellin, Simplesse™ (found in low-fat foods)

Food Sources: Egg substitutes, mayonnaise

Allergen: Milk

Alternate Names: Calcium, whey, lactose, casein

Food Sources: Cream, high-protein powder, sour cream, cottage cheese, cakes, puddings, hot chocolate, cheese, yogurt

Allergen: Fish or shellfish

Alternate Names: Agar, carrageenan

Food Sources: Worcestershire sauce, Caesar salad, dressing, cod liver oil

Allergen: Soy

Alternate Names: Guar gum, vegetable protein, lecithin, carob, starch, emulsifiers, flavorings, stabilizers

Food Sources: Vegetable broth or oil, tofu, soy sauce, tempeh, shortening, edamame, chorizo

Allergen: Wheat

Alternate Names: Gluten, semolina, modified food starch, MSG, vegetable gum

Food Sources: All-purpose flour, bleached flour, bran, American cheese, canned soup

Allergen: Peanuts

Alternate Names: Natural and artificial flavoring (read labels carefully to identify what kinds of artificial flavors might be in a food product)

Food Sources: Ice cream, chocolate, gravy, marzipan, egg rolls, candy, cookies

Allergen: Tree nuts

Alternate Names: Cashews, almonds, pecans, walnuts, Brazil nuts, hazelnuts (also called filberts), pine nuts, pistachios, macadamias, natural and artificial flavoring (read labels carefully to identify what kinds of artificial flavors might be in a food product)

Food Sources: Barbecue sauce, crackers, ice cream, foods with peanuts (may be cross-contaminated with tree nuts)

American Baby

Comments (1)

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