Food allergies in children dropped sharply in the years after new guidelines encouraged parents to introduce infants to peanuts, a study has found.
For decades, as food allergy rates climbed, experts recommended that parents avoid exposing their infants to common allergens. But a landmark trial in 2015 found that feeding peanuts to babies could cut their chances of developing an allergy by over 80 percent. In 2017, the National Institute of Allergy and Infectious Diseases formally recommended the early-introduction approach and issued national guidelines.
The new study, published Monday in the journal Pediatrics, found that food allergy rates in children under 3 fell after those guidelines were put into place — dropping to 0.93 percent between 2017 and 2020, from 1.46 percent between 2012 and 2015. That’s a 36 percent reduction in all food allergies, driven largely by a 43 percent drop in peanut allergies.
The study also found that eggs overtook peanuts as the No. 1 food allergen in young children.
The study did not examine what infants ate, so it does not show that the guidelines caused the decline. Still, the data is promising. While all food allergies can be dangerous, 80 percent of people never outgrow one.
“We’re talking about the prevention of a potentially deadly, life-changing diagnosis,” said Dr. Edith Bracho-Sanchez, a pediatrician at Columbia University Irving Medical Center in New York, who was not involved with the study. “This is real world data of how a public health recommendation can change children’s health.”
Scientists don’t fully understand what causes food allergies, but some believe that higher rates of C-section deliveries, early childhood exposure to antibiotics and our increasingly sanitized environments may play a role, said Jeanna Ryan, a physician assistant at University of Utah Health.
However, scientists have a working picture of how allergies might develop. Allergens first encountered through the skin — especially broken or inflamed skin — can prompt the immune system to mistake them for threats, said Dr. David Hill, a pediatric allergist at Children’s Hospital of Philadelphia who led the new study. But when food allergens are introduced through the gut, it can build tolerance.
For the past decade, studies have shown that introducing allergenic foods in infancy, as the immune system is developing, can help the body recognize food proteins as harmless, Dr. Hill said.
The latest national guidelines, established in 2021, recommend introducing common food allergens to all infants four to six months of age. Early introduction to the nine commonly allergenic foods a couple of times a week — like a pea-sized smear of peanut butter or a small bite of scrambled eggs, said Dr. Bracho-Sanchez — can help train an infant’s immune system.
The new study followed 125,000 children across nearly 50 pediatric practices. Allergies were determined by diagnosis codes and Epi-Pen prescriptions in infants’ electronic health records. Dr. Hill said the rate of allergy reduction in this study corresponded to about 57,000 fewer children with food allergies.
Because the study followed children only until age 3, it did not capture allergy rates in older children or if the drop in allergies would last into adolescence. But about two-thirds of children with allergies are diagnosed by age 3, said Dr. Zachary Rubin, a pediatric allergist in Illinois.
Experts say more research is needed to assess the impact of early-introduction guidelines on food allergy rates. Data from Australia and Sweden, for example, have found similar guideline changes were not tied to reductions in food allergies, although this may be explained by smaller sample sizes and more limited study designs, Dr. Rubin said. And other factors, such as improvements in eczema treatment, could help explain the shift in the United States, he added.
According to a 2021 survey, only about 17 percent of caregivers reported giving their infants peanuts before they were 7 months old. A recent clinical trial suggested that pediatricians recommended early peanut introduction to only 10 percent of high-risk infants, such as those with eczema, and to 35 percent of low-risk infants. Dr. Bracho-Sanchez attributes those rates to limited awareness of the early-introduction guidelines and the time constraints of pediatric visits.
“What we have been counseling on — the early introduction of potentially allergenic foods — is working to reduce allergies,” Dr. Bracho-Sanchez said. “And we know that it could work even better.”
Simar Bajaj covers health and wellness.
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