Large Trial Tests Whether Maternal Egg and Peanut Intake Prevents Infant Allergies

Eating more eggs and peanuts during pregnancy and breastfeeding did not significantly lower food-allergy risk in infants, a large randomised trial has found.

Published in the New England Journal of Medicine, the PrEggNut trial included 2,137 pregnant women whose babies had a strong family history of allergy. Women were randomly assigned to either a high-intake diet or a standard diet.

The high-intake group was asked to consume six eggs and 60 peanuts weekly from 23 weeks of pregnancy until four months after delivery, or until breastfeeding ended. The standard group was asked to consume no more than three eggs and 30 peanuts weekly.

Researchers assessed infants at about one year of age for IgE-mediated egg or peanut allergy using skin-prick testing and supervised oral food challenges when necessary.

Egg or peanut allergy occurred in 83 of 1,066 infants (7.8%) in the high-intake group, compared with 89 of 1,064 (8.4%) in the standard group. The difference was not significant. Similar results were seen for individual egg allergies, sensitisation and eczema.

The findings challenge the idea that higher maternal allergen exposure prevents allergies in babies. Researchers had proposed that exposure through the placenta and breast milk might establish immune tolerance before solid foods.

However, the study does not suggest that mothers should avoid eggs or peanuts. Current guidance does not recommend routine avoidance during pregnancy or lactation.

The trial had limitations. Allergy prevalence was about 8%, lower than the expected 16%, potentially limiting detection of a preventive effect. Adherence to the assigned diets was also moderate in this population.

The researchers concluded that higher maternal egg and peanut intake did not reduce or increase allergy risk. Evidence supporting timely introduction of egg and peanut directly into the infant diet remains important and relevant.

REFERENCE: Palmer DJ, Campbell DE, Nanan R, et al. Trial of a Maternal Diet Rich in Eggs and Peanuts to Reduce Infant Allergy. New England Journal of Medicine 2026;395(11):1090-1099. DOI:10.1056/nejmoa2605659