Israeli children suffer from peanut allergies at only one-tenth the rate of their Western counterparts with similar genetic backgrounds, and medical researchers think they know the reason: Eating Bamba, an iconic peanut-flavored snack considered a staple of Israeli childhood.
It seems that keeping small children away from peanuts at a young age actually makes them more susceptible to peanut allergies as they grow up, according to a paper published Monday in the New England Journal of Medicine. Exposing infants to peanuts before age one actually helped prevent a peanut allergy, lowering that risk by as much as 81 percent, doctors found. Instead of provoking an allergy, early exposure seemed to help build tolerance.
For years, parents of babies who seem likely to develop a peanut allergy have gone to extremes to keep them away from peanut-based foods. Now a major study suggests that is exactly the wrong thing to do.
"Several years ago, we found that the risk of the development of peanut allergy was 10 times as high among Jewish children in the United Kingdom as it was in Israeli children of similar ancestry," write the scientists ."This observation correlated with a striking difference in the time at which peanuts are introduced in the diet in these countries: in the United Kingdom infants typically do not consume peanut-based foods in the first year of life, whereas in Israel, peanut-based foods are usually introduced in the diet when infants are approximately 7 months of age, and their median monthly consumption of peanut protein is 7.1 grams. This finding led us to hypothesize that the early introduction of peanuts to the diet may offer protection from the development of peanut allergy."
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, called the results "without precedent" and said in a statement that they "have the potential to transform how we approach food allergy prevention."
His agency helped fund the study, the largest and most rigorous test of this concept. Results were published online Monday in the New England Journal of Medicine and discussed at an American Academy of Allergy, Asthma and Immunology conference in Houston.
A big warning, though: The babies in the study were checked to make sure they didn't already have a peanut allergy before they were fed foods that included peanuts, so parents of babies thought to be at risk for an allergy should not try this on their own.
The main finding — that early exposure to a problem food may keep it from becoming a long-term problem — should change food guidelines quickly, she predicted.
"Isn't it wild? It's counter-intuitive in certain ways and in other ways it's not," she said.
The editors of the NEJM found “the results of this trial are so compelling, and the problem of the increasing prevalence of peanut allergy so alarming, new guidelines should be forthcoming very soon." In the meantime, they recommend starting babies who do not yet test as allergic on peanut based foods at between four and eight months old, They write that while more research is needed, the study "makes it clear that we can do something now to reverse the increasing prevalence of peanut allergy."
"Before you even start any kind of introduction these children need to be skin-tested" to prevent life-threatening reactions, said Dr. Rebecca Gruchalla, an allergy specialist at the University of Texas Southwestern Medical Center in Dallas.
Also, small children can choke on whole peanuts, so smooth peanut butter or other peanut-based foods are safer, said Gruchalla, who wrote a commentary on the study in the journal.
Peanut allergies have doubled over the last decade and now affect more than 2 percent of kids in the United States and growing numbers of them in Africa, Asia and elsewhere. Peanuts are the leading cause of food allergy-related severe reactions and deaths. Unlike many other allergies, it is not outgrown with age.
Food allergies often are inherited, but research suggests they also can develop after birth and that age of exposure may affect whether they do.
Researchers at King's College London started this study after noticing far higher rates of peanut allergies among Jewish children in London who were not given peanut-based foods in infancy compared to others in Israel who were. The study involved more than 600 children ages 4 months to 11 months old in England. All were thought to be at risk for peanut allergy because they were allergic to eggs or had eczema, a skin condition that's a frequent allergy symptom.
All had been given skin-prick tests to make sure they were not already allergic to peanuts. They were put into two groups — 530 who did not show signs of peanut allergy and 98 others with mild-to-moderate reactions, suggesting an allergy might be developing.
Half of each group was assigned to avoid peanuts and the other half was to consume them each week, usually as peanut butter or Bamba, a peanut-flavored puff.
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