A large study credits guidelines to feed babies peanuts early in life for a steep drop in food allergies among young children. The decline the study captures was largely driven by a drop in peanut allergy.
The analysis reviewed records of 125,000 children seen at nearly 50 pediatric clinics across the U.S. Food allergies were identified by epinephrine auto-injector prescriptions and medical codes.
The study showed that food allergies in children under age 3 fell from 1.46 percent in 2012 to 2015 to 0.93 percent in 2017 to 2020. That’s a 36 percent decrease.
Peanut allergy showed the biggest decline, dropping by 43 percent, from 0.79 percent to 0.45 percent. That knocked peanuts out of the top allergen spot for this age group. According to this study, published in the journal Pediatrics, eggs are now No. 1 in kids.
What’s Behind the Dip?
Researchers attribute the drop to a major change in feeding advice. In 2017, updated U.S. guidelines recommended introducing peanut-containing foods to babies at 4 to 6 months. That reversed the previous advice to delay starting kids on peanuts and other potential allergenic foods until age 3.
“Our findings are encouraging. They signal that peanut and other food allergy rates are going in the right direction,” says lead study author Stanislaw Gabryszewski, MD, PhD. He’s an attending physician in the Division of Allergy and Immunology at Children’s Hospital of Philadelphia (CHOP).
For babies 4 to 6 months without a history of reactions, “early introduction is a concrete tool to help prevent food allergies.”
Dr. James Baker, director of the Mary H. Weiser Food Allergy Center at University of Michigan, says the study suggests changes in feeding recommendations are beginning to have a real-world impact. “The association very strong,” Baker says. “It elevates the concept of early feeding.”
However, the study could not directly measure what or how much parents fed their babies, so it can’t prove cause and effect.
In an editorial accompanying the study, three experts, including Northwestern University’s Dr. Ruchi Gupta, wrote that the study time frame was early days for implementing the early introduction guidelines. Given that, they caution it may be too soon to conclude the guidelines are behind a food allergy decline. They noted that while the study found a drop in peanut and milk allergy, egg allergy barely budged.
Allergy Decline Findings: Could It Be Other Factors?
Dr. Hugh Sampson, director emeritus of the Jaffe Food Allergy Institute at Mount Sinai Icahn School of Medicine, agrees. Improved diagnostic practices and reduced over-diagnosis may have contributed to the declining rates of diagnosis, he tells Allergic Living.
He notes that two “larger and more rigorous” studies in Australia and Sweden did not find a significant reduction in peanut allergy after similar guideline changes.
“While I fully believe in and advocate for early introduction of major food allergens, I have concerns about this study,” Sampson says.
Introducing food allergens early has been a sea change in approach. For years, parents were told to avoid feeding babies common allergens. In 2000, the American Academy of Pediatrics recommended delaying peanuts, eggs, or fish until age 3 in high-risk infants. Milk was to be postponed until age 1 and eggs until age 2.
“It was a knee-jerk response,” Baker says. “But it was wrong. It was probably just the opposite of what should have been done.”
IgE-mediated food allergy rates kept rising, with peanut allergy alone hitting 2.2 percent in one study.
The pediatricians group later rescinded its avoidance advice after research showed it afforded no protection.
LEAP Forward on Allergy Prevention
Meanwhile, clues emerged from Israel. There, infants who ate the puffed peanut snack Bamba had far fewer peanut allergies than children in U.K., where peanuts were commonly avoided.
The 2015 LEAP trial put early introduction to the test. About 640 babies ages 4 to 11 months at high risk of food allergy because of severe eczema or egg allergy were either put on a peanut-avoidance diet or were regularly fed Bamba. (Those with large positive skin tests to peanut were excluded for safety).
The study and a follow-up at age 5 found the babies fed peanut-containing foods had an 80 percent lower risk of developing peanut allergy. Babies already sensitized to peanut but who hadn’t yet shown signs of reacting benefited, too. Only 10 percent of those fed Bamba went on to develop the allergy, compared to 35 percent who avoided peanut.
In 2017, the National Institute of Allergy and Infectious Diseases convened an expert committee that recommended early peanut introduction at 4 to 6 months for allergy prevention. Most families could do this safely at home, while those with babies with severe eczema or egg allergy were advised to have skin or blood testing first.
A 2021 update expanded the recommendations to include peanut, egg, and other allergenic foods as part of a diverse diet, starting at 4 to 6 months.
Big Decline, But Gaps Remain
In the new study, the steepest drop was in peanut allergy. Gabryszewski estimates about one in 200 infants have been prevented from developing food allergies by early introduction.
Egg showed smaller declines, falling from 0.6 percent to 0.56 percent. Milk allergy fell from 0.38 percent to 0.21 percent.
In the editorial, the other experts note that it’s not clear why milk dropped so much, given that the 2017 guidelines focus was peanut. Or, why the egg effect was much smaller.
Baker adds that the benefits of early introduction are “best documented for peanut.” For other foods, it’s not yet known how much exposure is needed to be protective.
“The data around early feeding for other foods is much less substantial than for peanut,” he says. “While the concept still reigns true, the practice is not well defined, and certainly not as well defined as for peanut.”
Despite the recommendations, many families have yet to adopt the new approach. A 2022 national survey found that only 17 percent of parents introduced peanut before 7 months. About 59 percent had done so age 1.
Nearly 16 percent of parents introduced egg before 7 months. About 66 percent did so before 1 year. In 2020, just 29 percent of pediatricians fully followed the guidelines.
Some Kids Still Develop Allergies
Because the CHOP study followed children only until age 3, it did not measure allergy rates in older children. The peak age for a food allergy diagnosis is about 13 months old.
Even with early feeding, some children still develop food allergies. If parents should avoid anything, it’s blaming themselves for a child’s allergies, Baker says.
“A lot of children are still developing food allergies, even to peanut, despite this intervention,” he says. “We do not have a definitive understanding of the immunology of why and how this is happens and we need to continue to study the problem.”
Ilana Golant, CEO of the Food Allergy Fund, one of the study’s funders, said “CHOP’s findings offer hope that early introduction can help protect more children.” But “we also need to accelerate treatment options for those living with food allergies.”
Related Reading:
Early Introduction of Peanut Protects Against Allergy, LEAP Study Finds
Allergic Mom: How I Introduced My Baby to My Food Allergens
