Peanut Allergies Drop Steeply After Doctors Change Advice, Evidence Shows

Updated dietary guidelines in the US have significantly reduced the number of children with specific food allergies, reducing their need to avoid foods containing ingredients such as peanuts and eggs.

A major update to advice for preventing allergies in the US was published in 2015, with further revisions in 2017. A study led by a team from the Children's Hospital of Philadelphia (CHOP) now suggests that allergies have reduced in tens of thousands born in the years since.

The guidelines focus on anaphylactic food allergies, also known as immunoglobulin E (IgE)-mediated allergies due to the antibody involved. These allergic reactions happen quickly and can be severe or even life-threatening.

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In 2015, the guidance changed to recommend that peanut-based food products be introduced to children at a very young age, effectively training their immune systems to tolerate the ingredient. Previously, parents had been advised to avoid exposure til their child was at least 3 years old.

Drops were seen in peanut allergies after the introduction of new guidelines. (Gabryszewski et al., Pediatrics, 2025)

"Everyone has been wondering whether these landmark public health interventions have had an impact on reducing rates of IgE-mediated food allergies in the United States," says immunologist Stanislaw Gabryszewski, from CHOP.

"We now have data that suggest that the effect of this landmark public health intervention is occurring."

The researchers analyzed health data on almost 125,000 children born before and after the latest guidelines were introduced. Peanut IgE-mediated allergies dropped from 0.79 percent to 0.45 percent of the study group, while any IgE-mediated food allergy fell from 1.46 percent to 0.93 percent

Those are notable changes, suggesting that out of every 200 young children exposed to these foods, one avoided a potential allergy.

Smaller drops were seen across allergies as a whole. (Gabryszewski et al., Pediatrics, 2025)

"Our findings have relevance from those of us who treat patients to those caring for infants, and more awareness, education, and advocacy could further increase the positive results we observed in this study," says immunologist David Hill, from CHOP.

The study echoes findings from earlier this year, based on a smaller sample of children in Australia. In that research, the introduction of peanuts and eggs into diets at around six months of age was linked to a significant reduction in the number of allergies that developed.

While the 2015 guidelines – from the Learning Early About Peanut Allergy (LEAP) trial – focused on peanuts, they were expanded in 2021 to cover more IgE-mediated allergies. The changes weren't universally adopted right away, so seeing the effects at this relatively early stage is encouraging.

Nevertheless, an analysis of a greater number of children over a longer period of time will be needed to confirm the relationship between early exposure and fewer allergies, and give us more data on effective prevention strategies.

"Future studies could potentially explore specific feeding practices that help us better understand the timing, frequency, and dose of foods that optimize protection against food allergies," says Hill.

The research has been published in Pediatrics.