Reversing peanut advice prevented tens of thousands of allergy cases, researchers say : NPR

For years, parents have been advised not to give their children peanuts to prevent potentially dangerous allergies. But 10 years ago, landmark study found the opposite, stating that if children consume peanut products at an early age, they are much less likely to develop an allergy to them.

Health experts quickly took notice—and subsequent revisions to pediatric guidelines helped displace peanuts as the No. 1 cause of food allergies in children under 3 in the U.S., according to new study published in a peer-reviewed journal Pediatrics.

“Early exposure to allergens works,” Dr. David Hill, who led the study, tells NPR. “For the first time in recent history, it appears that we are beginning to slow down the food allergy epidemic in this country.”

Growing concerns about food allergies have changed parts of the American diet, from schools and camps banning peanut butter in sandwiches to airlines eliminating once-ubiquitous bags of salted nuts. In 2015 New England Journal of Medicine noted a fourfold increase in the prevalence of peanut allergy among children in the United States, indicating an increase from 0.4% in 1997 to more than 2% in 2010.

But when U.S. health guidelines changed in 2015 and 2017, so did that trend, according to Hill, a pediatric allergist at the Children's Hospital of Philadelphia who is also an assistant professor of pediatrics at the University of Pennsylvania.

“The prevalence of peanut allergy decreased by 43%,” says Hill, “and the prevalence of any food allergy decreased by 36%.”

He estimates that over the past decade, the changed guidelines have prevented peanut allergies in at least 40,000 children.

A turning point in peanut allergy prevention came in 2015, when the study was published which aimed to solve the mystery: why was peanut allergy 10 times higher among Jewish children in the UK than among Israeli children of similar origin? The researchers noted that while British and American parents kept their children away from peanut products, many Israeli parents regularly fed their children plump peanut snacks called Bamba.

Revised recommendations, including Dietary Guidelines for Americansencourages introducing peanut-containing foods to infants at high risk of peanut allergy as early as 4 to 6 months of age, according to recommendations published in 2017 National Institute of Allergy and Infectious Diseases.

Hill and colleagues examined rates of food allergies in young children before and after the publication of revised guidelines for peanuts and other allergens. They did this by analyzing the health data of more than 120,000 children in the United States, using records from dozens of different pediatric practices.

Dr. Corinne Keith, a pediatrics professor at the University of North Carolina at Chapel Hill who studies food allergy epidemiology, said she finds the study interesting, even if she's wary of reading too much into it. She did not participate in the study.

“I'm a little surprised by these results because I would have expected that we might have more diagnoses just because people have been thinking more about allergies” in the last decade, she says.

Part of the reason for her caution, Keith said, is that her own research has found that families are not fully implementing the new recommendations, in many cases because of concerns that exposing a child to peanut products could also put a sibling or parent with an allergy at risk.

Keith also says that doing a good study on the prevalence of food allergies is simply difficult. She notes that an influential 2015 study called JUMP (Early Study of Peanut Allergy) yielded definitive results in a large clinical trial involving hundreds of young children.

Hill and colleagues acknowledge that their study has limitations, such as the use of diagnostic codes that are not necessarily equivalent to actual allergy levels. Their data also does not include information about children's eating habits.

Still, he sees the study as another positive sign that the strategic shift is helping children. He adds that the benefits are far-reaching, since many peanut allergies last a lifetime.

“He’s very persistent,” Hill says. “Only about 10% of children who develop a peanut allergy will outgrow the allergy.”