In a trial carried out by researchers at King`s College London Department of Pediatric Allergy, 640 children aged 4-11 months who were considered at high risk of developing a peanut allergy due to pre-existing eczema and/or an allergy to eggs were put in two control groups. One group was connducted to consume food containing peanut three or more times a week, while the second group avoided peanuts until the age of five.
According to the results of the trial, less than 1 percent of children who consumed peanuts as directed had developed an allergy by the age of five, while 17.3 percent of children who had avoided peanut developed the allergy.
Professor Gideon Lack, who led the study, said in a press release, "This is an important clinical development and contravenes previous guidelines. Whilst these were withdrawn in 2008 in the UK and US, our study suggests that new guidelines may be needed to reduce the rate of peanut allergy in our children."
The received idea that avoidance is the best strategy to preventing allergy, on the assumption that allergies begin upon being exposed to the substance, began to be called into question more than a decade ago as scientists started to understand that the amount of peanut in the environment is much higher than previously thought, and makes complete avoidance difficult. Earlier studies showed that levels of peanut protein on the body were elevated for three hours after eating, and can also persist after the cleaning of household surfaces.
"Oral tolerance is an incompletely understood immunologic phenomenon," say the scientists in Monday`s paper. The team had previously compared allergy levels among children in Israel, where peanut snacks are commonly given to infants, and Jewish children in the UK of similar ancestry, and found that the development of peanut allergies was ten times as high in the UK, where children usually do not consume peanuts before the age of one.
The prevalence of peanut allergies in western countries has rocketed in recent years; a prevalence of 0.4 percent in the US in 1997 had risen to two percent in 2000, and is now the leading cause of anaphylaxis and death related to food allergy. The condition is also becoming apparent in Africa and Asia. In 2008 the American Academy of Pediatrics (AAP) retracted its advice for parents to avoid feeding peanuts to infants before the age of three, citing insufficient evidence for the recommendation.
In an editorial from the NEJM published on Monday, scientists declared that "because the results of this trial are so compelling, and the problem of the increasing prevalence of peanut allergy so alarming, new guidelines should be forthcoming very soon," before suggesting that in the meantime, "any infant between 4 months and 8 months of age believed to be at risk for peanut allergy should undergo skin-prick testing for peanut," and consequently begin a medically-administered diet of peanut protein.
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