Follow the science: Study shows early exposure to peanuts actually reduces allergies in children

A major new study released Monday in Pediatrics provides the strongest evidence yet that the National Institutes of Health’s recent recommendations on early peanut introduction to children have significantly reduced peanut allergies among youngsters.

Researchers analyzed health data from more than 1.3 million children under age 3 across the United States, comparing allergy rates before and after the NIH’s 2015 and 2017 guideline changes. They found that approximately 60,000 children have avoided developing peanut allergies as a result.

The study reported a 36% overall drop in IgE-mediated food allergies, from 1.46% of children in 2012–2015 to 0.93% in 2017–2020.

Peanut allergies specifically declined by 43%, from 0.79% to 0.45% in the same periods. After the NIH’s 2015 addendum, targeting infants at high risk for allergies, peanut allergy prevalence fell by more than 27%. Following the 2017 expansion of the recommendations to include moderate-risk infants, rates dropped by more than 40%.

Researchers noted that these declines track closely with adoption of the new approach, though by 2021 only 29% of pediatricians and 65% of allergists reported fully following the 2017 guidance. Conventional medical advice continues to follow the old protocols.

This is the first large-scale US study confirming that early allergen introduction works as intended, extending previous findings from smaller international trials.

For decades, health authorities advised parents to delay peanut exposure until age 3 or later, believing this would prevent sensitization. That changed after the Learning Early About Peanut Allergy (LEAP) trial, a landmark randomized controlled study published in 2015. The LEAP trial found that introducing peanuts between 4 and 11 months of age reduced allergy risk by 81% in high-risk infants by age 5.

In response, the NIH’s National Institute of Allergy and Infectious Diseases issued a 2015 addendum recommending early peanut introduction for infants with severe eczema or egg allergy. In 2017, the guidance was broadened to include moderate-risk infants. By 2021, it was further updated to recommend early introduction of peanuts and other common allergens—such as eggs and tree nuts—for all infants between 4 and 6 months of age.

The science behind the change is based on the “dual-allergen exposure hypothesis,” which proposes that early oral exposure to allergenic foods builds immune tolerance, while avoidance increases the risk of sensitization through skin exposure, especially in babies with eczema.

Recent NIH-funded follow-up studies, including LEAP-On and LEAP-Trio, show that early peanut feeding can reduce allergy risk by more than 70% well into adolescence. Although overall adoption has been gradual—only about 17% of parents were introducing peanuts before 7 months as of 2021—the new Pediatrics data suggest even partial uptake has led to major population-level benefits.

Public health experts say the findings reinforce the importance of early introduction, while acknowledging persistent barriers such as caregiver hesitation, misinformation, and limited access to pediatric guidance. Peanut allergy still affects about 2% of U.S. children, but the trend line appears to be improving.

For parents, the NIH recommends introducing peanut-containing foods around 4–6 months of age, once babies are ready for solids. Smooth peanut products, such as diluted peanut butter or peanut powder mixed into purees, are safest. Parents of high-risk infants are encouraged to consult their pediatrician before starting, though routine allergy testing is not necessary for most.