A follow-up study to a randomized trial has found that introducing peanuts to infants and continuing consumption until age 5 years may provide lasting protection against peanut allergy, even if peanut consumption is later reduced.

The original Learning Early About Peanut Allergy (LEAP) trial demonstrated that peanut consumption from infancy to age 5 years could reduce the risk of peanut allergy at age 5 years by 81%. A subsequent extension of that trial, LEAP-On, showed the effect persisted after 1 year of peanut avoidance from ages 5 to 6 years.

In the latest follow-up, the LEAP-Trio study, published in the New England Journal of Medicine Evidence, researchers assessed 508 of the original 640 LEAP trial participants at an average age of 13 years. They found that peanut allergy was more prevalent in participants from the original peanut avoidance group compared to the original peanut consumption group (15.4% vs. 4.4%).

Study participants in both groups reported varying frequencies and amounts of peanut consumption between ages 6-12 years, including periods of avoiding peanut products. Immunological markers differed between the groups, with the peanut consumption group showing different levels of certain peanut-related antibodies compared to the avoidance group.

"Today's findings should reinforce parents' and caregivers' confidence that feeding their young children peanut products beginning in infancy according to established guidelines can provide lasting protection from peanut allergy," stated NIAID Director Jeanne Marrazzo, M.D., M.P.H. “If widely implemented, this safe, simple strategy could prevent tens of thousands of cases of peanut allergy among the 3.6 million children born in the United States each year.”

The study suggested that early peanut introduction may induce long-term tolerance, even if consumption is later reduced, without the need for consistent peanut consumption throughout childhood and early adolescence. For detailed advice on safely introducing peanut into an infant's diet, consult the Addendum Guidelines for the Prevention of Peanut Allergy in the United States.

The LEAP-Trio study was conducted by the NIAID-funded Immune Tolerance Network under the leadership of Dr. Gideon Lack from King's College London. The study was funded by the National Institute of Allergy and Infectious Diseases and co-funded by the National Peanut Board and The Davis Foundation.