The study, known as the LEAP-Trio trial, found that starting peanut consumption as early as around 4 months of age, and continuing regularly until around 5 years old, was associated with a remarkable 71% reduction in peanut allergy among adolescents in the United Kingdom.

The research, conducted by scientists from King's College London and the United States, explored the long-term effects of early peanut introduction on allergy prevalence. The study included data from the LEAP trial, which focused on infants with eczema and egg allergy and followed them until the age of 5. At that age, the prevalence of peanut allergy was found to be about 17% in the group of children who avoided peanuts, compared to only 3% in the group that consumed peanut products. This represented an 81% relative reduction in peanut allergy.

In the LEAP-Trio trial, approximately 500 children were assessed again at around age 12 to determine the prevalence of peanut allergy. The results revealed that peanut allergy remained "significantly more prevalent" among those who originally avoided peanuts, with about 15% of them having a peanut allergy. On the other hand, only about 4% of those who consumed peanuts had a peanut allergy, indicating a 71% reduction in prevalence at the LEAP-Trio time point.

These findings suggest that introducing peanuts to children at an early age not only reduces the risk of developing peanut allergies but also provides lasting tolerance to peanuts into adolescence. Professor Gideon Lack, an author of the study, explained that this phenomenon is based on oral tolerance induction, which has been observed for many decades in experimental animals. Young animals that are fed allergenic foods like peanuts, milk, or eggs do not develop allergies to these foods later in life.

The American Academy of Pediatrics previously recommended delaying the introduction of peanuts until three years of age but ended that recommendation in 2008. In 2019, the AAP updated its guidelines to state that early introduction of peanuts may prevent peanut allergy.

Peanut allergy is a growing public health concern in the United States, affecting approximately 2% of children under 18 years old, which amounts to nearly 1.5 million individuals. Peanuts are known to cause severe allergic reactions, including potentially life-threatening anaphylaxis.

Dr. Jeanne Marrazzo, director of the US National Institute of Allergy and Infectious Diseases, emphasized that parents and caregivers should have confidence in feeding their young children peanut products according to established guidelines. Implementing this safe and simple strategy could prevent tens of thousands of peanut allergy cases among the 3.6 million children born in the United States each year.

It is important to note that introducing peanuts to infants should be done under the guidance of a pediatrician. For children at low risk of allergies, peanuts can be introduced around 4 to 6 months old, with the recommendation of gradually increasing the amount. However, children with severe eczema and egg allergy should consult an allergist before early introduction.

To ensure safety, it is recommended to use smooth peanut butter mixed into a puree instead of using whole peanuts or chunky peanut butter to avoid choking hazards.

The study's findings provide reassurance to parents and caregivers that early introduction of peanuts can significantly reduce the risk of peanut allergies in children. However, it is important to consult with healthcare professionals for personalized guidance on introducing peanuts to infants and young children.