New Guidelines Downplay Role of Diet in Preventing Pediatric Allergies: An Expert Interview With Frank Greer, MD

Kathleen Louden


April 21, 2008

Editor's Note:

The American Academy of Pediatrics (AAP) recently issued an updated policy statement that reviews the clinical evidence regarding nutritional options during pregnancy, lactation, and the first year of life that may or may not affect the development of atopic disease. Published in the January issue of Pediatrics and online, the new recommendations discuss maternal dietary restriction, breastfeeding, timing of introduction of complementary foods, and hydrolyzed formulas.

This clinical report, developed by the AAP's nutrition and allergy expert panels, replaces the organization's 2000 policy statement on hypoallergenic infant formulas. The old statement included provisional recommendations for dietary management for the prevention of atopic disease, some of which have changed under the new policy.

The new report defines atopic disease as atopic dermatitis, asthma, and food allergy, all of which are increasing. To learn more about the implications of this report, writer Kathleen Louden interviewed Frank Greer, MD, chairperson of the AAP's Committee on Nutrition and lead author of the report. He is Professor of Pediatrics at the University of Wisconsin.

Medscape: What was the impetus for developing this new clinical report?

Dr. Greer: There was a lot of folklore built around this idea that something the mother eats during pregnancy or lactation or something she feeds her baby has long-term impact for allergy disease. Traditionally a lot of pediatricians have recommended not to give infants eggs, fish, peanuts, or any nuts in the first year of life.

Medscape: Were there new research findings?

Dr. Greer: Yes. It makes absolutely no difference. For instance, if you're going to have a peanut allergy, it has nothing to do with when you were introduced to peanuts. If a mother eats peanuts during pregnancy or lactation or if she feeds her 6-month-old peanut butter, it has no effect on whether you get peanut allergy. If you're going to get it, you're going to get it. There's even evidence from one study that if you don't introduce egg into the infant's diet until after 6 months, the baby is more likely to develop an egg allergy. And European recommendations came out the same month that ours did that if you introduce wheat between 4 and 6 months of age, your baby will be less likely to have a gluten allergy.[1] We didn't go that far. This is one of the very few areas where ESPGHAN [European Society for Paediatric Gastroenterology, Hepatology and Nutrition] policy differed from the AAP's January statement.

Medscape: So expecting and breastfeeding mothers don't have to restrict their diet by avoiding common food allergens?

Dr. Greer: Correct. The evidence is just not there that pregnant and lactating women restricting their diet in any way affects whether their baby gets allergic disease.

Medscape: This is a major change from the recommendations the AAP made in 2000, isn't it?

Dr. Greer: We've never had a statement this strong. The statement that this replaced said that it's probably not a good idea to introduce these [potentially allergenic] foods until after the infant is of age. [The former recommendation was to delay giving dairy products until 1 year; eggs until 2 years; and peanuts, tree nuts, and fish until 3 years of age.] These recommendations were not based on evidence but on expert opinion. The new statement is evidence based. There have been a number of recent studies, particularly looking at the effect on allergy of nutritional interventions during pregnancy and lactation.

Medscape: Were there any interventions that had a protective effect?

Dr. Greer: The only thing that may be of benefit is exclusive breastfeeding for at least 4 months. These babies don't have as much atopic disease, especially atopic dermatitis. That's one of the few things you can do. There seems to be something in breast milk that protects against allergies. The effect is even stronger if your child is at high risk for allergy, which means having at least 1 parent or sibling with allergic disease. If you can't breastfeed for 4 months and your child is at risk for allergy, there is probably benefit as far as preventing or delaying atopic dermatitis if you feed your baby one of the hydrolyzed infant formulas -- either an extensively or partially hydrolyzed formula.

Medscape: How will this new report have an impact on clinical practice, especially for pediatricians?

Dr. Greer: That's a good question. I can tell you that of all the statements the Committee on Nutrition has published in the past 8 years, none have gotten as much interest from the press and from allergy groups as this one. We've also sent out announcements in the American Academy of Pediatrics newsletter. The message is getting out there. I'm not sure the pediatricians are picking up on it.

Now we can tell mothers: If you have exclusively breastfed for 4 months and your child is not at risk for allergy, you can introduce any food at 6 or 8 months or whatever. [Solid foods should still not be introduced before the infant is 4-6 months old, according to the report.] In children at risk for atopic disease, simply avoiding foods for a certain time may delay the onset of allergy, but it doesn't prevent allergy.

Medscape: What about if an infant shows a predisposition for allergy?

Dr. Greer: Atopic dermatitis is typically diagnosed before 4 months of age. If a baby is breastfeeding yet develops atopic dermatitis and thus shows a propensity for allergy, I suspect the clinical guidance would be to not give the baby peanuts [or other common food allergens].

Medscape: What types of future studies are needed before researchers and the Academy can draw firm conclusions about atopy prevention through dietary interventions?

Dr. Greer: We would like to see more long-term studies, especially for the prevention of asthma in the adolescent period. There are some studies out there but not with large enough numbers.


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