The standard advice for preventing children’s peanut allergies—keep them from eating peanuts as long as possible—may have the problem backward, according to a large scientific study conducted in England and recently published in the New England Journal of Medicine. Kids who ate small amounts of peanut early in their life were 80 percent less likely to develop the sometimes-fatal allergy than kids who strictly avoided the nuts.
If the trial result holds up—and it is being hailed as ground-breaking—it could change how pediatricians advise parents to feed young children, and potentially could stall the soaring rates of peanut allergy that have caused peanuts and peanut butter to be banned on airlines and in schools.
“In Western countries, 1.5 percent to 3 percent of children have peanut allergy to varying degrees of severity, so quantitatively, it’s quite a serious problem,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health, told The Plate. (Fauci’s institute funded the study.) “It’s not a trivial allergic response: Some children can develop anaphylaxis, the worst kind of allergic reaction, and can get into serious trouble and even die from it. And the numbers are getting bigger, as the years go by. So it’s been very frustrating.”
The study’s results run counter to long-standing advice, formulated by the American Academy of Pediatrics in 2000, that kids at risk of allergy should not eat any peanuts until they are at least three years old. (The AAP actually backed off that advice in a rewrite in 2008, but many parents still heed the original prohibition.) The results suggest instead that training kids’ immune systems early with small amounts of allergen protects them from the overwhelming, life-threatening reaction they might experience later on.
The study grew out of an observation made six years ago by Dr. George Du Toit of King’s College London that Jewish kids living in the United Kingdom and in Israel had similar lives but very different allergy levels: the English kids were 10 times more likely to have peanut allergies. Through a questionnaire given to more than 5,000 kids in each country, Du Toit determined that parents of the British kids were following the advice to avoid any peanuts, while parents of the Israeli kids let them eat a popular snack—Osem Bamba, a Cheetos-like corn puff tumbled in peanut butter—starting when they were just a few months old.
The study published Monday (and released simultaneously at the annual meeting of the American Academy of Allergy, Asthma and Immunology) took that observation and turned it into a rigorous prospective trial. Du Toit, Dr. Gideon Lack (also of Kings College) and their colleagues in the “Learning Early About Peanut Allergy” (LEAP) Study recruited more than 600 children who were between four and 11 months old and followed them for five years. The kids in the study were believed to be at risk of developing a peanut allergy because they already had shown symptoms of an egg allergy, or of eczema, indicating their immune systems were primed for overreactions.
The researchers checked the kids to see whether they were already allergic; they ruled out highly allergic kids for whom peanut protein would have been dangerous, but accepted both non-allergic kids and ones whom a skin test showed to be mildly sensitized. Then they randomly assigned the children either to avoid peanuts entirely, or to eat the same snack as the Israeli kids—enough to take in six grams of peanut protein per week, divided into at least three meals.
The children were checked periodically during the trial and then evaluated for any allergy at five years old. Among the children who started the trial with no sensitivity, nearly 14 percent who did not eat any peanut products developed an allergy, compared to less than 2 percent of those who did. Among the children who were already slightly sensitive to peanuts, but did not eat any peanuts as they grew, 35 percent developed an allergy, compared to almost 11 percent of the ones who ate the snack.
In other words, the peanut exposure, via the snack, not only kept children with no pre-existing sensitivity from developing an allergy; it also reduced the likelihood that children already on the road to an allergy would actually develop one.
That result is so striking—a 70 to 80 percent reduction depending on the class of kids, according to an accompanying editorial—that Fauci said NIAID will soon bring together pediatricians, immunologists and other experts to develop guidelines for translating the results into medical practice. In the meantime, Dr. Todd Mahr of the Gunderson Health System in Wisconsin, chair of the American Academy of Pediatrics’ section on allergy and immunology, said it may be possible for worried parents to put the findings to real-life use now.
“We do not envision peanut should become a ‘first food’ for infants, but would suggest that an infant who is healthy and has tolerated other first foods without difficulty, and is developmentally ready to ingest peanut (not single peanuts, which are a choking hazard, but peanut as butter, or in soft snacks), could have this food incorporated into the diet,” he told me.
Families who think a child may be headed toward peanut allergy, because he or she already has eczema or another food allergy, may be able to use these results to defuse it, he added. They “should discuss with their allergist/pediatrician the option of ‘copying’ the study under direct medical supervision,” he said. “This may require allergy skin testing and a supervised food challenge. This approach, to copy the study, would include a commitment to maintain peanut in the diet on a regimen.”
The questions that have not yet been answered include whether the effect the study observed will last, or whether children need to keep eating small doses of peanut to maintain their immune balance. (Du Toit and Lack plan a second round to answer that question.) It also isn’t known whether the results can help children who are already allergic to peanuts, because those kids were ruled out from the study to start with. And it won’t change the situation in schools and on airplanes, because those restrictions exist to protect kids who are already allergic.
But if the results are put into practice, it is possible that someday, there might be fewer allergic kids. “I don’t think you can end peanut allergy,” Fauci said. “But you can dramatically diminish its incidence.”