Close up of peanuts
March 6, 2016

Early peanut exposure lowers allergy chance later in life, study finds

Peanut allergies are a tough nut to crack, but a new study out of the New England Journal of Medicine offers fresh hope for prevention by demonstrating that exposing infants to peanuts may actually protect against later allergies.

“Food allergies are a growing concern, not just in the United States but around the world," said National Institute of Allergy and Infectious Diseases director Anthony S. Fauci, M.D. "For a study to show a benefit of this magnitude in the prevention of peanut allergy is without precedent. The results have the potential to transform how we approach food allergy prevention."

Food allergies have become more prevalent across the years—some of the people who eat gluten-free actually need to, after all—and peanut allergies are no exception. In the last decade alone, the occurrence of peanut allergy across North America and the UK has doubled. Now, between 1-3 percent of all children across the USA, Western Europe, and Australia have peanut allergies—and very few of them will outgrow it. It develops early in life, and there is no cure—meaning that prevention of the allergy in the first place may just be the solution we need.

Early exposure can work

Researchers led by Dr. Gideon Lack from Kings College London had previously discovered that peanut exposure could be the answer. In the first large, well-controlled study of this kind, 640 infants aged 4-11 months, all of whom were considered high-risk for developing peanut allergy (as they already had exhibited severe eczema and/or an egg allergy), were either regularly exposed to peanuts 3 or more times per week or avoided them entirely until age 5. The researchers verified avoidance or consumption both by a questionnaire and by measuring the levels of peanut dust near the children’s beds.

Children who were exposed to peanuts were more than 80 percent less likely to develop an allergy than children who avoided peanuts.

The results were obviously extremely important, but there was no indication of whether the effects would last in the long-term, especially if all participants stopped eating peanuts.

Following up with more questions

And so, the researchers decided to extend the original study, which was known as LEAP (Learning Early About Peanut Allergy), following 556 of the children (274 previous peanut consumers, 282 abstainers) from this research in the study now titled LEAP-ON. Now, all were asked to avoid peanuts for a year. And, as before, peanut dust samples and surveys confirmed compliance with instructions.

12 months later, an oral food challenge was given to each participant to test their allergy status. And, as it turned out, only 4.8 percent of the original peanut consumers were allergic, while 18.6 percent of the abstainers were—still a 74 percent relative difference between the two groups.

"The LEAP-ON findings exceeded our expectations and demonstrated that the early consumption of peanuts provided stable and sustained protection against the development of peanut allergy in children at greatest risk for this allergy," said Dr. Lack in a statement. "This protective effect occurred irrespective of whether the children completely avoided peanut for one year or continued to eat it sporadically."

Or in a nutshell: Periodic lapses in peanut consumption won’t likely lead to the development of the allergy, at least not for the span of a year. The researchers are planning a longer-term study with the participants, though, to fortify this data.

"This study offers reassurance that eating peanut-containing foods as part of a normal diet—with occasional periods of time without peanut—will be a safe practice for most children following successful tolerance therapy," said Dr. Gerald Nepom, director of the Immune Tolerance Network. "The immune system appears to remember and sustain its tolerant state, even without continuous regular exposure to peanuts."

"We believe this new information will inform the public health debate on infant guidelines and shed light on the mechanisms that underpin the induction of oral tolerance," added Dr. Lack.

However, this does not mean you should start feeding your infant peanuts right away if you don’t already.

"The study also excluded infants showing early strong signs of having already developed peanut allergy; the safety and effectiveness of early peanut consumption in this group remains unknown and requires further study. Parents of infants and young children with eczema and/or egg allergy should consult with an Allergist, Pediatrician, or their General Practitioner prior to feeding them peanut products," Lack emphasized.

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