Peanut consumption beginning in the first 11 months of life
He prevalence of peanut allergy among children in Western countries has doubled in the past 10 years, reaching rates of 1.4 to 3.0 percent and peanut allergy is becoming apparent in Africa and Asia. This allergy is the leading cause of anaphylaxis and death due to food allergy and imposes substantial psychosocial and economic burdens on patients and their families.
Peanut allergy develops early in life and is rarely outgrown. Clinical practice guidelines from the United Kingdom in 1998 and from the United States in 2000 had recommended to remove peanuts from an infant’s diet who were at high risk for allergy and from the diets of their mothers during pregnancy and lactation. However, studies failed to show that elimination from the diet prevented allergies.
Dr. Gideon Lack, MD, Head of the Children’s Allergy Service at Guy’s and St Thomas’ NHS Foundation Trust, Professor of Pediatric Allergy at King’s College London and designed the clinical trial Learning Early About Peanut Allergy (LEAP), which determined the best strategy to prevent peanut allergy in young children. Dr. Lack, lead researcher of this study and colleagues examined strategies of peanut consumption and avoidance to determine which strategy is most effective in preventing the development of peanut allergy in infants at high risk for the allergy.
Dr. Anthony S. Fauci, MD, Director of the National Institute of Allergies and Infectious Diseases (NIAID) commented “Food allergies are a growing concern, not just in the United States but around the world.” “For a study to show a benefit of this magnitude in the prevention of peanut allergy is without precedent. The results have the potential to transform how we approach food allergy prevention.”
LEAP compared two strategies to prevent peanut allergy; consumption or avoidance of dietary peanutin infants who were at high risk of developing peanut allergy because they already had egg allergy and/or severe eczema, an inflammatory skin disorder.
For the study researchers randomly assigned 640 infants with severe eczema, egg allergy, or both to consume (six grams of peanut protein per week in their diets) or avoid peanuts until 60 months of age. Participants, who were at least 4 months but younger than 11 months of age at randomization, were assigned to separate study cohorts on the basis of preexisting sensitivity to peanut extract, which was determined with the use of a skin-prick test; one consisting of participants with no measurable wheal after testing and the other consisting of those with a wheal measuring 1 to 4 mm in diameter.
Clinical assessments were undertaken at baseline (when participants were between 4 months and 11 months of age) and at the ages of 12, 30, and 60 months; between-visit scheduled telephone consultations were conducted weekly until participants reached 12 months of age, every 2 weeks from 12 months to 30 months of age, and monthly thereafter. Additional clinic visits were scheduled to evaluate aversion to peanut or refusal to eat peanut (Bamba or peanut butter) or suspected peanut allergy.
The results showed Among the 530 infants in the intention-to-treat population who initially had negative results on the skin-prick test, the prevalence of peanut allergy at 60 months of age was 13.7 percent in the avoidance group and 1.9 percent in the consumption group were allergic to peanuts; this absolute difference in risk of 11.8 percentage points represents an 86.1percent reduction of peanut allergy in children who began early, continuous consumption of peanut compared to those who avoided peanut.
All 98 children in the group with positive results on the initial skin-prick test were evaluated and were included in the intention-to-treat analysis. At 60 months of age, 35.3 percent of the avoidance group and 10.6 percent of the consumption group were allergic to peanuts; the absolute difference in risk of 24.7 percent. The team found a 70 percent reduction in the prevalence of peanut allergy
According to Dr. Daniel Rotrosen, MD, director of NIAID’s Division of Allergy, Immunology and Transplantation, “While recent studies showed no benefit from allergen avoidance, the LEAP study is the first to show that early introduction of dietary peanut is actually beneficial and identifies an effective approach to manage a serious public health problem.”
A follow-up study called LEAP-On will ask all LEAP study participants to avoid peanut consumption for one year. These results will determine whether continuous peanut consumption is required to maintain a child’s tolerance to peanut.
Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy. New England Journal of Medicine, 2015; 150223141105002 DOI: 10.1056/NEJMoa1414850
NIH/National Institute of Allergy and Infectious Diseases Public Release