New Research Shows Peanut Allergy May Be Prevented Early in Life

Groundbreaking results of the first randomized clinical trial to prevent food allergy in a large group of high-risk infants were presented today at the annual scientific meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) in Houston. Published in the prestigious New England Journal of Medicine, researchers led by Gideon Lack, M.D., of Kings College London, found that sustained consumption of a peanut-containing snack by babies at high risk for developing peanut allergy prevented them from developing peanut allergy. Peanut consumption achieved an 86 percent reduction in peanut allergy at age 5 among children who had negative skin prick tests to peanut at study entry, and a 70 percent reduction in peanut allergy among those who were sensitized to peanut (positive skin prick test) at the beginning of the study.

The Learning Early About Peanut allergy (LEAP) study was funded by Food Allergy Research and Education (FARE) and the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH. It was designed and conducted by the Immune Tolerance Network, a collaborative network of clinical researchers sponsored by NIAID.

Investigators tested the hypothesis that regularly eating foods containing peanut – if started during within the first year of life – could elicit a protective immune response rather than an allergic reaction. Researchers had previously noted that Jewish children in the United Kingdom have a 10-fold higher risk of developing peanut allergy compared to Israeli children of similar ancestry. Children in Israel are typically introduced to a peanut-containing snack at about 7 months of age, while those in the UK did not eat peanut in the first year of life.

More than 600 children between 4 months and 11 months of age were enrolled in the LEAP study to compare the likelihood of developing peanut allergy in children who either ate or avoided peanut until the age of 5.  All of the infants in the study were considered at high risk for developing peanut allergy because they had severe eczema and/or egg allergy.

The children exposed to peanuts ate a peanut-containing snack at least three times a week while the other group did not eat any foods containing peanut. By the age of 5, just 3 percent of the children who ate the snack developed peanut allergy, while 17 percent in the avoidance group developed peanut allergy. In high-risk infants, sustained consumption of peanut starting in the first 11 months of life was highly effective in preventing the development of peanut allergy, the authors wrote.

“For decades allergists have been recommending that young infants avoid consuming allergenic foods such as peanut to prevent food allergies. Our findings suggest that this advice was incorrect and may have contributed to the rise in the peanut and other food allergies,” Lack said.

FARE CEO James R. Baker, Jr., MD, noted that these findings provide significant evidence that the timing of the introduction of peanut into an infant’s diet can influence whether the child develops peanut allergy.

“FARE remains committed to investing in research that helps us better understand food allergy as a disease and provides hope for new treatments – including approaches that can help prevent people from developing allergies to food. This study will likely have a significant impact on approaches to prevent the development of peanut allergy in future generations. We are very pleased to have supported it,” Baker said.

“It is also important to note that this study was conducted as a formal, controlled clinical trial, with a well-defined infant cohort to give a definitive answer on the role of early food avoidance in prevention of peanut allergy. Despite these impressive results, children and adults with peanut allergy should not attempt to introduce foods that contain peanut into their diets without first consulting with their physician.” 

In this trial, very early sensitization was seen in babies with no history of peanut consumption. The authors proposed a “dual allergen hypothesis,” to explain this paradox. This hypothesis suggests that the manner in which a food allergen is first introduced may play a role in sensitization.  For example, early environmental peanut exposure through the skin may lead to the sensitization noted in babies with no history of peanut consumption, “whereas oral exposure may lead to tolerance.”  The authors also note that early oral introduction of peanuts even prevented allergy in sensitized infants (who have allergic antibodies to peanuts), albeit with slightly less efficacy.  This suggests that pre-existing sensitization may not be a barrier to this approach.

Whether the children in the trial continue to remain protected will be investigated further in the LEAP-On study.

“Our findings demonstrate that early, sustained consumption of peanut products is associated with a substantial and significant decrease in the development of peanut allergy in high-risk infants. Conversely, peanut avoidance is associated with greater frequency of clinical peanut allergy than consumption, questioning the utility of deliberate avoidance of peanut as a strategy to prevent allergy,” the authors conclude.

Visit the New England Journal of Medicine to read an editorial about the study by Rebecca S. Gruchalla, M.D., of the University of Texas Southwestern Medical Center and Hugh A. Sampson, M.D., chair of FARE’s Medical Advisory Board and the Kurt Hirschhorn, M.D./Children’s Center Foundation Professor of Pediatrics and dean for Translational Biomedical Sciences at the Icahn School of Medicine at Mount Sinai in New York City.

FARE will be reporting on additional research findings from the AAAAI meeting in the next edition of FARE News. For information on food allergy research, please visit

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