By Markita Lewis, MS, RD
In May 2024, new research published in the New England Journal of Medicine Evidence (NEJM Evidence) provided additional insights on the continued benefits of early introduction for peanut allergy prevention. This research was supported in part by the National Peanut Board (NPB), a dedicated funder of peanut allergy research.
Thanks to a proactive approach to peanut allergy research near the beginning of the board’s founding, NPB has funded over $36 million dollars of peanut allergy research over the past two decades. One of the earliest relationships built between the board and the allergy world was with world-renown pediatric allergist and allergy researcher Dr. Gideon Lack and his team at Kings College in London.
NPB helped support the original research from this lab on the impact of early introduction of allergens and allergy prevention – the Israel UK observational study and the LEAP Study, which showed that early introduction of peanuts could reduce the risk of developing a peanut allergy. Now, nearly a decade later, we are still gaining additional insights from this landmark study that has changed early feeding guidelines around the world through the LEAP Trio study.
The LEAP Trio study builds upon the original LEAP and LEAP-On trials which demonstrated that early introduction of peanut was effective in helping prevent the development of peanut allergy and that this protection persisted, even after avoiding peanuts for a year (between ages 5 to 6 years) after successful early introduction. The current LEAP Trio cohort consists of participants of the LEAP and LEAP-On studies, siblings of the original LEAP participants, and the biological parents of the LEAP participants.
In late May 2024, the article titled Follow-up to Adolescents after Early Peanut Introduction for Allergy Prevention was published in NEJM Evidence. This study examined the continued persistence of peanut tolerance and the rate of peanut allergy at the age 144 months (12 years) in LEAP and LEAP-On participants.
The study’s population consisted of 508 out of the original 640 children enrolled in the LEAP study, which included both the early peanut consumers and the peanut avoiders. All participants went through an oral food challenge and were surveyed on their recent peanut consumption.
Researchers found that the original peanut consumption group had continued allergy protection and an overall lower prevalence of peanut allergy compared to the avoidance group (4.4% to 15.4%, respectively).
The LEAP-Trio study uncovered additional impacts of early introduction on environmental exposure to allergens and subsequent peanut sensitization and allergy in the younger siblings of LEAP participants. This holds importance to learning more about allergy development due to increased interest in the dual allergen exposure hypothesis amongst allergy researchers.
The dual allergen exposure hypothesis generally states that while oral exposure to potential allergens can induce tolerance to an allergy, exposure through impaired skin leads to sensitization and potential allergy development. As it relates to peanuts, early introduction of peanut-containing foods between 4-6 months can help reduce risk of peanut allergies while skin exposure to peanuts or peanut dust in the context of eczema or another condition that causes skin impairment may increase the risk of allergies.
In this additional analysis, 144 younger siblings of the original LEAP study’s peanut avoiders and 154 younger siblings of peanut consumers underwent skin prick tests and evaluation of allergy-specific labs to determine peanut sensitization. The younger siblings of those who were peanut consumers had a higher rate of sensitization nearing significance to peanut (30.4%) compared to the younger siblings of the peanut avoiders (20%). Additionally, there was a higher rate of peanut allergies overall (10% vs 5%), though this difference was not statistically significant.
Taking an additional deeper look at younger siblings of the peanut consumers, those who were introduced to peanut within the first year had a significantly lower rate of sensitization (18.3%) compared to those who weren’t introduced to peanut within the first year(44.4%).
What does this all mean? While household exposure to peanut allergens may have somewhat increased sensitization to peanuts in the younger siblings of the original LEAP participants, early introduction of peanuts to these younger children still reduced the risk of peanut sensitization and potential allergy development.
While the LEAP Trio has not yet come to an end, it has shed light on the continued protection of early introduction on peanut allergy prevention for infants. NPB continues to have pride in our role of supporting groundbreaking and transformative allergy research to work towards our goal of eradicating peanut allergies. For additional information on allergy prevention, please visit PreventPeanutAllergies.org.
References
- Du Toit G, Katz Y, Sasieni P, et al. Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy. J Allergy Clin Immunol. 2008;122(5):984-991. doi:10.1016/j.jaci.2008.08.039
- Du Toit G, Roberts G, Sayre PH, et al. Randomized trial of peanut consumption in infants at risk for peanut allergy [published correction appears in N Engl J Med. 2016 Jul 28;375(4):398. doi: 10.1056/NEJMx150044]. N Engl J Med. 2015;372(9):803-813. doi:10.1056/NEJMoa1414850
- Du Toit G, Huffaker MF, Radulovic S, et al. Follow-up to Adolescence after Early Peanut Introduction for Allergy Prevention. NEJM Evid. 2024;3(6):EVIDoa2300311. doi:10.1056/EVIDoa2300311
- Lack G. Early exposure hypothesis: where are we now?. Clin Transl Allergy. 2011;1(Suppl 1):S71. Published 2011 Aug 12. doi:10.1186/2045-7022-1-S1-S71
- Lack G, et al. An unintentional randomized trial of early environmental exposure to peanut: the younger siblings of LEAP participants. J of Clin Immunol. 2024; 153(2S):SAB367. Published 2024 Feb.