Study Information 

Title: Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy. Autors: DuToit, G et al. The LEAP Study team.

Publication: New England Journal of Medicine, 2015.

Online access:


UK and US researchers have published a much-anticipated clinical trial that has demonstrated what recent research has shown:  delaying or avoiding introduction of peanuts to high-risk infants, rather than reducing peanut allergy, actually increases the prevalence of allergy at 5 years of age.   Peanut allergy prevalence among children in Western countries has doubled in the past 10 years, reaching rates of 1.4 to 3.0%, and peanut allergy is also becoming apparent in Africa and Asia. It is the leading cause of anaphylaxis and death due to food allergy, along with significant social and economic burdens on patients and their families.


Peanut allergy develops early in life and is rarely outgrown. Clinical practice guidelines from the U.K. (1998) and from the U.S. (2000) recommended the exclusion of allergenic foods from the diets of infants at high risk for allergy and from the diets of their mothers during pregnancy and lactation. However, the Canadian Paediatric Society’s 2013 guidelines acknowledged the need for more research, while recommending no restriction of maternal diet during pregnancy or lactation, nor delaying the introduction of any specific solid food beyond six months of age.



Review of Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy

Provided by Coleen Nolan, RD


Previous work showed the risk of developing peanut allergy was 10 times higher among Jewish children in the U.K. compared to Israeli children of similar ancestry.  This observation correlated with a significant difference in the times of peanut introduction in the diet in these countries: in the U.K. infants typically do not consume peanut-based foods in the first year of life, whereas in Israel, peanut-based foods are usually introduced in the diet when infants are approximately 7 months of age (median monthly consumption of peanut protein is 7.1 g).  This finding led the researchers to hypothesize that early introduction of peanuts to the diet may offer protection from the development of peanut allergy.


The LEAP (Learning Early about Peanut Allergy) team of pediatric allergy experts randomly assigned 640 UK infants with severe eczema, egg allergy, or both to consume or avoid peanuts until 60 months of age. Participants, who were 4-11 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.  The primary outcome, assessed independently in each cohort, was the proportion of participants with peanut allergy at 60 months of age.  No placebo product was provided due to logistical and financial constraints.


Results showed among the 530 infants who initially had negative results on the skin-prick test, the prevalence of peanut allergy at 60 months of age was 13.7% in the avoidance group and 1.9% in the consumption group (P<0.001).  Among the 98 participants who initially had positive test results, the prevalence of peanut allergy was 35.3% in the avoidance group and 10.6% in the consumption group (P = 0.004). 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. There was no significant between-group difference in the incidence of serious adverse events.


The lack of a placebo group was an acknowledged weakness of the study.  The authors concluded that early introduction of peanuts significantly decreased the frequency of the development of peanut allergy among children at high risk for this allergy and modulated immune responses to peanuts.  The results of the LEAP study lends further support to the theory that avoiding peanuts as a means to prevent allergy is likely not a useful strategy.  Studies are underway to examine the long-term efficacy of early introduction of peanut to reduce allergy risk, even after cessation of intake (see the LEAP-On Study).



Randomized Trial of Peanut Consumption in Infants at Risk for Peanut Allergy

George Du Toit, M.B., B.Ch., Graham Roberts, D.M., Peter H. Sayre, M.D., Ph.D., Henry T. Bahnson, M.P.H., Suzana Radulovic, M.D., Alexandra F. Santos, M.D., Helen A. Brough, M.B., B.S., Deborah Phippard, Ph.D., Monica Basting, M.A., Mary Feeney, M.Sc., R.D., Victor Turcanu, M.D., Ph.D., Michelle L. Sever, M.S.P.H., Ph.D., Margarita Gomez Lorenzo, M.D., Marshall Plaut, M.D., and Gideon Lack, M.B., B.Ch., for the LEAP Study Team* New England Journal of Medicine, Feb. 2015.


Dietary exposures and allergy prevention in high-risk infants.  Canadian Paediatric Society.  A joint statement with the Canadian Society of Allergy and Clinical Immunology.  Dec. 2013

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