A new study reported today in the New England Journal of Medicine demonstrates that consumption of a peanut-containing snack by infants who are at high-risk for developing peanut allergy prevents the subsequent development of allergy. The "Learning Early About Peanut allergy" (LEAP) study, designed and conducted by the Immune Tolerance Network (ITN), with additional support from FARE, and led by Professor Gideon Lack at Kings College London, is the first randomized trial to prevent food allergy in a large cohort of high-risk infants.
The prevalence of peanut allergy has doubled over the past 10 years in the USA and numerous other countries. Peanut allergy, which now affects approximately 1.5% of young children, can cause adverse reactions ranging from development of hives and abdominal pain to severe anaphylaxis that requires immediate treatment with epinephrine. Because of the risk of anaphylaxis, children with peanut allergy are advised to avoid peanut in their diet and must carry an epinephrine autoinjector kit with them for use in event of a severe reaction.
Peanut allergy is an aberrant response by the body's immune system to harmless peanut proteins in the diet. This study was based on a hypothesis that regular eating of peanut-containing products, when started during infancy, will elicit a protective immune response instead of an allergic immune reaction. The LEAP randomized controlled study enrolled over 600 children between 4 and 11 months of age at high risk for peanut allergy to test whether consumption or avoidance of peanut until age 5 years would result in decreased incidence of peanut allergy. Children in the peanut consumption arm of the trial ate a peanut-containing snack-food at least three times each week, while children in the peanut avoidance arm did not ingest peanut-containing foods.
The infants enrolled in the study had severe eczema and/or egg allergy, which put them at high risk of developing peanut allergy. Of the children who avoided peanut, 17% developed peanut allergy by the age of 5 years. Remarkably, only 3% of the children who were randomized to eating the peanut snack developed allergy by age 5. Therefore, in high-risk infants, sustained consumption of peanut beginning in the first 11 months of life was highly effective in preventing the development of peanut allergy.
As Professor Lack, the lead investigator for this study, points out, "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."