At a pediatric conference in Israel, Gideon Lack, a specialist in pediatric allergy at King’s College London, asked how many of the doctors in the room had treated a child for a peanut allergy. To his surprise, only a fraction of the number he was expecting raised their hands. This expectation was based on how doctors in Europe and the United Kingdom typically reply to this question at his talks. Lack realized that while in Israel children start eating nuts at a very young age — at around seven months — in the U.K., this rarely happens before a child has turned one. To determine whether this was due to a biological factor, the doctor carried out a trial with members of some Jewish communities in the United Kingdom, who have similar genetic traits to those of Israel. The results, published in 2008, showed that Jewish children in the U.K. had a prevalence of peanut allergy that was 10-fold higher than that of Jewish children in Israel.
Between 1998 and 2000, pediatric guidelines in the U.K. and the U.S. recommended that allergenic foods be excluded from the diets of babies at a high risk of allergy. Mothers were even advised to avoid these products during pregnancy and lactation. This was based on the idea that exposure to allergens could trigger allergies. But in the following decade, allergies in Western countries doubled, and the recommendation was removed.
In 2005, Lack published the results of a randomized trial called LEAP in the New England Journal of Medicine. The study reached a clear conclusion: “The early introduction of peanuts significantly decreased the frequency of the development of peanut allergy among children at high risk for this allergy.”
In a new study — presented at a videoconference hosted by the Science Media Center — Lack and other researchers set out to define the optimal age to introduce peanut products into a child’s diet, and the target populations to prevent allergies. The results found that peanut allergy would fall an estimated 77% if peanut was introduced to a baby’s diet at six months of age, or four months of age in the case of infants with eczema. If peanut was not introduced until an infant was 12 month old, the estimated reduction was only 33%.
One of the authors of the study, Mary Feeney from King’s College, said that introducing solid food did not have to mean an end to breastfeeding. She added that peanut can be introduced in the form of smooth peanut butter — not whole or broken peanuts, which are a choking hazard — or in milk, and introduced three times a week.
During the presentation, Graham Roberts, from the University of Southampton, showed an illustration to visualize the potential of early peanut introduction on allergy prevalence. According to Roberts, every year around 13,000 children develop a peanut allergy in the U.K. By introducing peanuts to infants’ diets at six months of age, “it would prevent 10,000 children from developing a peanut allergy each year,” he said.
In the study, the authors conclude that “in countries where peanut allergy is a public health concern, health care professionals should help parents introduce peanut products into their infants’ diet at four to six months of life.”
Sign up for our weekly newsletter to get more English-language news coverage from EL PAÍS USA Edition