Ten years ago, public health experts recommended a radical shift in pediatric care. Children should not be shielded from common allergens like peanuts, they said, but exposed early to prevent eventual intolerance.
Now, a new study from doctors at the Children's Hospital of Philadelphia suggests the approach is working.
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The research, published Monday in Pediatrics, found declines in peanut and other immunoglobulin E-mediated food allergies following the updated guidelines. IgE-mediated food allergens also include milk, egg, soy, wheat, tree nuts, fish and shellfish.
The rate of peanut allergies dropped from 0.79% to 0.45%, while the rate of any IgE-mediated food allergies fell from 1.46% to 0.93%, the study found. Based on this data, the CHOP team estimated that 1 in 200 babies exposed to allergens early in infancy was prevented from developing a food allergy.
The results affirm the updated recommendations, which were issued in 2015 and again in 2017. The push for early exposure followed an influential 2015 study, which found that introducing 4- to 11-month-old babies with severe eczema or egg allergies to peanuts reduced their risk of developing a peanut allergy by 81%. While the initial guidelines were geared toward children at risk for IgE-mediated food allergies, they now recommend early exposure to peanuts, eggs and other allergens for all infants at 4-6 months — as long as they have not had a prior reaction.
To study the impact of the guidelines, the researchers drew infants' health records from a multi-state database, monitoring each for two years to see if a food allergen developed. The patients were divided into three groups: "preguidelines" kids observed from 2012 to 2014, "postguidelines" kids observed from 2015 to 2017 and "postaddendem guidelines" kids observed from 2017 to 2019.
Along with the overall decrease in food allergies, the CHOP team noticed other interesting trends. While peanuts were the top source of allergies in the preguidelines group, they were the second-most common allergen in the postguidelines and postaddendum groups. Eggs became the leading source of food allergies for these children.
Cow's milk was the third-most common allergen in all three groups. The rates of milk allergies, however, declined over time. The researchers theorized that the drops in peanut and cow's milk allergies, even as egg allergies stayed relatively steady, "suggest that early introduction practices may be variably applied to specific foods, underscoring the need to track the evolving landscape of early food introduction patterns."
"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," Dr. David Hill, an attending physician at CHOP and one of the study co-authors, said in a statement.
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