Children who are given peanut products from infancy are significantly less likely to develop peanut allergies by early adolescence, according to a recent study.
The findings, which followed more than 500 participants until the age of 12, confirmed what earlier research has found but tracked the children for longer than most previous work, reports The Washington Post.
Michelle Huffaker, one of the authors of the study (published in NEJM Evidence) and the director of translational medicine at the University of California-San Francisco, said it was “extraordinary” to be able to demonstrate that early exposure to peanuts tied to a lower rate of peanut allergy lasting at least to age 12.
“It was certainly what we’d hoped to see,” she said. Another study, referred to as the LEAP trial, examined children up to the age of five, but “it wasn’t clear that that was necessarily enough time to prove long-term tolerance”, she added.
Many parents remain concerned about giving their babies peanut products and aren’t aware that it is safe and recommended by experts, a study found last year.
In 2017, the American Academy of Paediatrics began advising that high-risk children should be introduced to peanuts as early as four to six months, after the child had been tested for a peanut allergy.
The guideline, adopted after the LEAP trial was published, was a reversal of previous advice, released in 2000, that told parents to avoid peanuts for their babies until at least the age of three.
Health authorities have warned that whole peanuts and chopped peanuts can be choking hazards for infants. But using peanut butter, which can be spread thinly on other food or mixed with breast milk, formula or purées, while peanuts can be finely ground, can reduce the risk, they said
Huffaker said that to expose an infant to peanuts, “there are various options, but plain old peanut butter mixed in warm water can work for a four-month-old – it doesn’t need to be anything fancier than that”.
The researchers on the NEJM Evidence study – led by King’s College London, the University of California-San Francisco and the Children’s Allergy Service at the Guy’s and St Thomas’ NHS Foundation Trust in London – previously examined peanut allergies in children up to age five, again at age six, and then continued following the group for another six years for the latest study.
At about 12, 15.4% of children who had avoided peanuts in infancy to the age of five had developed an allergy, compared with 4.4% who had consumed peanuts.
The numbers are higher than would be expected in the general population because the study examined children who were already at a higher risk of having a peanut allergy, like those with egg allergies or eczema, Huffaker said.
Food allergies among children in the United States doubled from 2000 to 2018. Multiple likely causes include under-exposing children to potentially allergenic substances.
Across various age groups, the rate of peanut allergy prevalence in the US was between 0.6% and 2.6%.
Study details
Follow-up to Adolescence after Early Peanut Introduction for Allergy Prevention
George Du Toit, Michelle Huffaker, Lars Dunaway et al for the Immune Tolerance Network LEAP-Trio Trial Team
Abstract
Background
A randomised trial demonstrated consumption of peanut from infancy to age five prevented the development of peanut allergy. An extension of that trial demonstrated the effect persisted after one year of peanut avoidance. This follow-up trial examined the durability of peanut tolerance at age 144 months after years of ad libitum peanut consumption.
Methods
Participants from a randomised peanut consumption trial were assessed for peanut allergy following an extended period of eating or avoiding peanuts as desired. The primary end point was the rate of peanut allergy at age 144 months.
Results
We enrolled 508 of the original 640 participants (79.4%); 497 had complete primary end point data. At age 144 months, peanut allergy remained significantly more prevalent in participants in the original peanut avoidance group than in the original peanut consumption group (15.4% [38 of 246 participants] vs. 4.4% [11 of 251 participants]; P<0.001). Participants in both groups reported avoiding peanuts for prolonged periods of time between 72 and 144 months. Participants at 144 months in the peanut consumption group had levels of Ara h2-specific immunoglobulin E (a peanut allergen associated with anaphylaxis) of 0.03 ± 3.42 kU/l and levels of peanut-specific immunoglobulin G4 of 535.5 ± 4.98 μg/l, whereas participants in the peanut avoidance group had levels of Ara h2-specific immunoglobulin E of 0.06 ± 11.21 kU/l and levels of peanut-specific immunoglobulin G4 of 209.3 ± 3.84 μg/l. Adverse events were uncommon, and the majority were related to the food challenge.
Conclusions
Peanut consumption, starting in infancy and continuing to five years, provided lasting tolerance to peanut into adolescence irrespective of subsequent peanut consumption, demonstrating that long-term prevention and tolerance can be achieved in food allergy.
NEJM article – Effect of avoidance on peanut allergy after early peanut consumption (Open access)
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