Early Peanut Eating Cut Allergy Rates Years Later in High-Risk Children

CATEGORY: IMMUNE HEALTH

The peanut eating stopped at age 5. Children in the LEAP trial then ate peanut freely or not at all, as they pleased, and many went long stretches without any. The protection did not fade. At age 12, the children who had eaten peanut regularly from infancy to age 5 were 71% less likely to have a peanut allergy than the children who had avoided it in those early years: 4.4% against 15.4%.¹ Because infants had been assigned to eat or to avoid at random, the result carries more weight than studies that simply observe habits.

The Old Advice Was the Opposite

Peanut allergy is among the most common food allergies in children. It usually lasts for life, and it can cause anaphylaxis, a severe whole-body allergic reaction that can be life-threatening. For decades the standard advice was to keep peanut away from young children at risk. The LEAP research program tested the reverse proposition: that a baby’s immune system learns to treat a food as harmless by meeting it early and often. Doctors call that state tolerance.

640 Infants, Then 508 of Them Again at 12

The original trial enrolled 640 infants aged 4 to 11 months in the United Kingdom, all at high risk of peanut allergy because of severe eczema, egg allergy, or both. Eczema is an itchy, inflamed skin condition. Clinicians assessed every infant before anything began. Half were assigned to eat peanut-containing foods regularly until age 5, half to avoid peanut entirely. Allergy testing at age 5 found peanut allergy in 3.2% of the eating group and 17.2% of the avoidance group, a reduction of 81%. Restrictions then ended and everyone chose freely. LEAP-Trio brought 508 of those children back at age 12 and tested them again, in most cases with an oral food challenge, in which a child eats small, increasing amounts of peanut under close medical supervision.¹ The follow-up ran in NEJM Evidence.

38 of 246 Against 11 of 251

At 12, allergy was far more common among those who had avoided peanut as babies: 38 of 246 children, against 11 of 251 in the early-eating group.¹ Blood tests pointed the same way, showing an antibody pattern associated with tolerance in the early-eating group. Side effects in the study were uncommon and mostly related to the supervised food challenges.¹ Two things bound the finding. Whole peanuts are a choking hazard for infants, which is why the trial used peanut-containing foods instead. And these were high-risk infants evaluated and followed by allergy specialists, so what the trial describes is early introduction under medical guidance rather than any particular feeding routine at home.¹

Pooled trials agree. A 2024 review of three randomized trials of early peanut introduction, this one among them, found peanut allergy roughly 69% less common in the infants given peanut early.² In US primary-care records, diagnoses in children under 3 ran about 35% lower after national guidelines shifted toward early introduction, though a before-and-after comparison shows association rather than cause.³

Key Takeaways

• Eating peanut regularly from infancy to age 5 was linked to a 71% lower rate of peanut allergy at age 12: 4.4% against 15.4%.¹
• The protection persisted even though children in both groups often went long periods without peanut after age 5, which points to durable immune tolerance.
• The infants were at high risk of peanut allergy and were assessed and monitored by clinicians, so the findings reflect early introduction under medical supervision.

References

1. Du Toit G, Huffaker MF, Radulovic S, et al. Follow-up to Adolescence after Early Peanut Introduction for Allergy Prevention. NEJM Evidence. 2024;3(6):EVIDoa2300311. link
2. Tuballa A, Connell D, Smith M, et al. Introduction of allergenic food to infants and allergic and autoimmune conditions: a systematic review and meta-analysis. BMJ Evidence-Based Medicine. 2024;29(2):104–113. link.
3. Gabryszewski SJ, Dudley J, Faerber JA, et al. Guidelines for early food introduction and patterns of food allergy. Pediatrics. 2025;156(5):e2024070516. link.