Big LEAP: Eating Peanuts in Infancy Reduces Allergy Risk Later

Kate Johnson

February 23, 2015

HOUSTON — When infants at high risk of developing peanut allergy consume peanut on a regular basis, their risk can be dramatically reduced, according to LEAP — the Learning Early About Peanut study.

The work was published online in the New England Journal of Medicine to coincide with its presentation here at the American Academy of Allergy, Asthma & Immunology 2015.

"Early, sustained consumption of peanut products was associated with a substantial and significant decrease in the development of peanut allergy in high-risk infants," according to Gideon Lack, MB BCh, from King's College London and Guy's and St. Thomas' National Health Service Foundation Trust, United Kingdom, and colleagues.

"Conversely, peanut avoidance was associated with a greater frequency of clinical peanut allergy than was peanut consumption, which raises questions about the usefulness of deliberate avoidance of peanuts as a strategy to prevent allergy," the investigators explain.

"It's a landmark study. I think this is so dramatic that I hope it doesn't take long to change practice," Hugh Sampson, MD, from the Jaffe Food Allergy Institute at the Icahn School of Medicine at Mount Sinai in New York City, told Medscape Medical News.

It's a landmark study.

In an editorial accompanying the publication, Dr Sampson and Rebecca Gruchalla, MD, from the University of Texas Southwestern Medical Center at Dallas, call for an immediate change to clinical practice on the basis of the LEAP findings.

"This is proof," Dr Sampson explained. "I thought there would be an effect, but I never thought it would be that big."

"The LEAP study makes it clear that we can do something now to reverse the increasing prevalence of peanut allergy," explain Drs Sampson and Gruchalla. "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."

Anybody 4 to 8 months of age, "or maybe it should be 4 to 6 months, needs to be skin tested. And if it's negative, I'd get them on peanut," said Dr Sampson.

The open-label, single-center, controlled LEAP trial involved 640 infants who were considered to be at high risk of developing peanut allergy because of severe eczema, egg allergy, or both. Median age was 7.8 months.

LEAP Study

Participants were randomly assigned to peanut consumption or peanut avoidance. All underwent a baseline skin-prick peanut test, and those assigned to consumption were given a baseline food challenge.

Children who tested negative on the initial skin-prick test underwent primary prevention. They were given 2.0 g of peanut protein in a single-dose food challenge.

Children who tested positive on the initial skin-prick test underwent secondary prevention. They were given incremental doses up to a total of 3.9 g.

Anyone who had a reaction to the food challenge was moved into the avoidance group.

Anyone who passed the food challenge was moved into the consumption group and fed at least 6 g of peanut protein per week, distributed in three or more meals, until they reached the age of 60 months.

Primary prevention and secondary prevention were assessed separately for the primary study outcome, which was peanut allergy at 60 months determined with an oral food challenge.

The intervention was effective as both primary and secondary prevention for reducing the prevalence of peanut allergy.

Table. Prevalence of Peanut Allergy After the Intervention

Prevention Avoidance Group, % Consumption Group, % P Value
Primary 6.0 1.0 .008
Secondary 33.1 6.8 <.001


"This intervention was safe, tolerated, and highly efficacious. In the intention-to-treat analysis, peanut consumption was associated with an 86% reduction in peanut allergy at 60 months of age among participants who had had negative results on a peanut-based skin-prick test at study entry and with a 70% reduction among those who had had positive test results at study entry," the LEAP investigators report.

There were no deaths in the study population and no significant differences in the rate of hospitalization or serious adverse events between the avoidance and consumption groups.

However, "nine participants who were randomly assigned to peanut consumption subsequently discontinued consumption," the investigators explain. Additionally, "although peanut-specific IgE levels increased over time in both the peanut-avoidance and peanut-consumption groups, there were fewer participants in the consumption group with very high IgE levels at 12, 30, and 60 months."

Despite calling for an immediate change in guidelines, Drs Sampson and Gruchalla acknowledge that many questions remain unanswered, such as how much peanut protein children should consume and how frequently, and how long children will remain protected from developing allergy, especially if they stop consuming peanuts.

"This landmark study is the first controlled study to demonstrate a significant decrease in peanut allergy with the early introduction of peanut," said session moderator Mary Beth Fasano, MD, from the University of Iowa Carver College of Medicine in Iowa City. However, she added, "we do not know if similar findings apply to other foods."

This study was supported by grants from the National Institute of Allergy and Infectious Diseases; Food Allergy and Research Education; the Medical Research Council and Asthma UK; the United Kingdom Department of Health, through a National Institute for Health Research comprehensive Biomedical Research Center award to Guy's and St. Thomas's NHS Foundation Trust, in partnership with King's College London and King's College Hospital NHS Foundation Trust; the National Peanut Board; and the United Kingdom Food Standards Agency. Dr Lack reports holding stock and stock options in DBV Technologies. One of his coauthors, Helen Brough, MB BS, from King's College London and Guy's and St. Thomas' NHS Foundation Trust, reports receiving grant support from Action Medical Research and study materials from Stallergenes, Thermo Scientific, and Meridian Foods. Dr Sampson and Dr Gruchalla have disclosed no relevant financial relationships.

American Academy of Allergy, Asthma & Immunology (AAAAI) 2015. Presented February 23, 2015.


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