Copyright The Philadelphia Inquirer
Fewer children are developing peanut allergies following an update to the prevention guidelines in the U.S., researchers at the Children’s Hospital of Philadelphia found in a new study. For years, parents were told to avoid exposing their babies to any peanuts, for fear of tempting an allergy. Meanwhile, rates of childhood peanut allergies more than tripled from 1997 to 2008. The guidelines changed almost a decade ago when a landmark trial found that simply introducing children aged four to 11 months to peanut-containing foods could reduce their risk of developing a peanut allergy by more than 80%. In response, the National Institute of Allergy and Infectious Diseases released updated guidance in 2017, recommending parents introduce their children to peanut products as early as four to six months. In the years after, peanut allergies declined by 43% among U.S. children under 3, while food allergies overall fell by 36%, according to the CHOP study published in Pediatrics last week. The team looked at electronic health record data from more than 120,000 children across multiple years, up until the start of 2020. “Although the early introduction guidelines have been around for a while now, we didn’t have concrete data showing that it is translating into meaningful change here in the United States,” said Stanislaw Gabryszewski, first author on the study and a CHOP allergist. The study suggests that for every 300 infants, one fewer child would develop a peanut allergy if the families introduced the nuts early. That’s tens of thousands fewer peanut allergy diagnoses across the U.S. The difference is so large that peanuts are no longer even the top allergen in young children — eggs took that spot, the team found. “What surprised me was the magnitude of the reduction,” said David Hill, the study’s senior author and a CHOP allergist. He hopes this study can help spread the word about the updated guidelines for any families who are unaware or hesitant about them. “It’s really important that we get word out that this is safe and effective,” he said. In 2008, scientists found that Jewish children in the U.K. were 10 times more likely to have peanut allergies compared to their counterparts in Israel, despite having similar genetic backgrounds. The difference came down to a popular peanut-flavored snack called Bamba that children in Israel commonly eat from an early age. This observation laid the groundwork for the new early introduction approach, the science of which ultimately comes down to differences in how the immune system acts in the gut versus the skin. The immune system in the gut has evolved to be good “at seeing foreign things and assessing if they’re dangerous or not,” Hill explained. After all, the gut comes into contact with inert dust, proteins, carbohydrates, and other substances in food every day, and even houses billions of bacteria. The immune system in the skin, by contrast, “is very poised to react,” Hill said. The skin is a barrier surface, meaning, unlike the gut, things aren’t supposed to be able to permeate it. It’s more anxious about any potential intruders. That’s especially true if a child has eczema, a common skin condition that causes dry and inflamed skin and is a major risk factor for developing food allergies. “If the immune system recognizes a food allergen for the first time through the skin, it’s much more likely to interpret that food allergen as foreign and dangerous,” Hill said. In other words, if the immune system is a police force scattered across different parts of the body, the officers in the skin are much more likely to make false arrests compared to the officers in the gut. Introducing a food allergen in the diet early on increases the odds that the gut sees it before the skin has a chance to react. “Your immune system learns how to tolerate that allergen,” Gabryszewski said. The latest guidelines from major medical organizations, published in 2021, recommend early introduction of peanut, egg, and other major allergens at ages four to six months. Gabryszewski personally recommends diluting peanut butter with water or breast milk, and keeping peanut-containing foods in the child’s diet about three times a week. The vast majority of children will be able to tolerate peanut when it’s introduced early, he emphasized, meaning there’s no need to get an EpiPen or be prepared to treat a reaction. In the small event that a child reacts to peanuts, “the first reactions are not very severe,” he added. Hill recommends keeping peanut products in the child’s diet until a year of life, so the immune system learns to tolerate the food. The amount each time can be the size of a pea or a pinky nail. “You want to go for exposure, not nutrition,” Hill said. As a pediatrician at CHOP, Lisa Ravener was more informed than most parents when it came to the new guidelines. She made sure to introduce peanut-containing foods early on, through thinning out peanut butter in breast milk or formula. Two of her children did not develop peanut allergies. But her middle child, Jake, still had a worrisome reaction while the family was at a party. Then 18 months old, Jake picked up a Bamba, put it in his mouth, and spit it out. “It seemed like it burned him or hurt him,” Ravener said. A few minutes later, hives formed around his mouth. She sent a photo of the hives to Hill, her friend from residency, who told her to bring Jake in for testing. The results showed he did have an allergy. Fortunately, he was young enough to benefit from another method of exposure called oral immunotherapy, a treatment that involves providing patients with controlled, low-level exposure to the allergen over time. Ravener started Jake with one crushed up peanut M&M, and worked him up to five M&Ms a day. Through visits to the hospital, she was able to gradually increase his exposure over time. After four and a half years, Jake was cleared of his allergy. “As your kids get older, and they’re not always with you, that’s one of the more scary times when they have allergies,” Ravener said. “Having him be at this stage of life, and not having to feel worried about that anymore is very nice,” she added. She still gives Jake a dish of honey-roasted peanuts a few nights a week, so he doesn’t backslide. As a pediatrician, she counsels her own patients on early introduction. When the new guidelines first came out, some families struggled to accept the change. “You have other family members or grandparents who are like, ‘No, no, no, when I had kids, they said that you shouldn’t do it until they’re two, three years old. It’s way too early,’” Ravener said. However, nowadays, more parents seem to be aware when she mentions the guidelines. The positive findings from the study will help reinforce that for people, she added. “There is something that you can do early on to help protect your kids from these allergies,” Ravener said. “It really feels empowering.”
