Can exposing babies to common food allergens help prevent food allergies later on?

DEAR DOCTOR K:

In a recent column you said that parents should give babies peanut products to help prevent peanut allergies. Does the new advice also apply to other common food allergens, like eggs or cow’s milk?

DEAR READER:

To answer your question I turned to my colleague Dr. Claire McCarthy, a primary care pediatrician at Boston Children’s Hospital. For decades, the standard advice recommended by allergy specialists was to hold off on giving babies foods that commonly cause allergic reactions. Parents were advised not to give egg, dairy, seafood or wheat in their child’s first year. And parents were told to wait until two or three years to give peanuts or other nut products. It turns out that was bad advice.

What’s changed? A few years ago, research began to suggest that there was no particular benefit in waiting to give those foods. Children seemed to develop food allergies whether their parents waited or not. And then a year ago, research showed that giving babies peanut products earlier in life made it less likely that they would develop a peanut allergy.

A new study in The New England Journal of Medicine confirms last year’s study. The study involved more than 1,000 exclusively breast-fed 3-month-old babies who were divided up into two groups. The parents of one group were told to give their babies only breast milk for six months. The parents of the other group were told to give their babies six foods that often cause allergic reactions: peanut products, eggs, wheat, cow’s milk, sesame and whitefish.

The result: Fewer children in the second group ended up with peanut or egg allergy when tested between ages 1 and 3 years.

The researchers didn’t find decreases in allergies to the other foods. But — this is important — they didn’t find increases, either.

Now, there’s more we need to study and understand. For example, how much do babies need to eat to prevent allergy? For which foods does this work? But given that food allergies affect about one in 13 children, it is exciting news.

There are a couple of important safety caveats:

  • If your baby has a known or suspected food allergy, or there is a history of food allergies in the family, talk to your doctor before starting any solid foods.
  • Don’t ever give babies or toddlers actual peanuts; they are a choking hazard. Instead, use peanut butter (smooth), oils and pastes.

Why did doctors once advise against giving babies peanuts (or peanut products) for two or three years, and why did the advice change? Doctors thought that an infant’s developing immune system might react badly to foods, like peanuts, to which allergies develop.

But then a U.S. peanut allergy specialist visiting Israel discovered that few Israeli children develop peanut allergies — and that most Israeli children are fed peanut products in the first years of life. At that point, precious research funds were freed up, a study done, and the truth revealed.