High maternal egg-peanut intake not associated with reduced infant allergy

1. In this randomized controlled trial, high maternal consumption of eggs and peanuts during pregnancy and lactation did not reduce IgE-mediated egg or peanut allergy in high-risk infants at one year. 

2. Maternal and infant safety outcomes were similar between groups. 

Evidence Rating Level: 1 (Excellent)

Study Rundown: Food allergy can emerge early in infancy, particularly among children with a strong family history of allergic disease. Although contemporary prevention strategies emphasize timely introduction of allergenic foods directly to infants, immune responses to food proteins may begin before solid foods are introduced. Allergens can reach the fetus through amniotic fluid and the breastfed infant through human milk, raising the possibility that greater maternal exposure during pregnancy and lactation could promote immune tolerance. Prior evidence has not supported maternal avoidance of allergenic foods, but whether deliberately increasing maternal intake could prevent food allergy remained uncertain. This trial, termed PrEggNut, found that higher consumption of egg and peanut beginning during pregnancy and continuing through early lactation did not reduce the occurrence of IgE-mediated egg or peanut allergy among infants at elevated familial risk of allergic disease. Findings were similarly neutral for individual egg and peanut allergy, sensitization, and eczema. Strengths included the multisite design, standardized allergy testing and food challenges, and consistent findings across various subgroup analyses. Important limitations included a lower-than-anticipated allergy rate, incomplete adherence, and a select high-risk population. Contemporary guidance encouraging early infant allergen introduction may also have lowered background allergy risk in both groups. Overall, increasing maternal egg and peanut consumption during pregnancy and lactation did not provide clear additional protection against infant food allergy. 

Click to read the study in the NEJM (New England Journal of Medicine) 

Relevant Reading: Randomized Trial of Introduction of Allergenic Foods in Breast-Fed Infants 

In-Depth [randomized controlled trial]: This multisite, single-blind randomized controlled trial enrolled 2,137 pregnant women across four Australian cities between 2018 and 2024. Eligible women were less than 23 weeks pregnant with a singleton pregnancy, planned to breastfeed for at least four months, and were carrying a fetus with at least two biologic family members with medically diagnosed allergic disease. Women with egg or peanut allergy were excluded. Participants were randomized 1:1 to a high egg-peanut diet consisting of at least 6 eggs and 60 peanuts weekly or a standard diet permitting no more than 3 eggs and 30 peanuts weekly. The intervention continued from enrollment through four months postpartum while breastfeeding. The primary outcome was IgE-mediated egg or peanut allergy at one year, established using standardized skin-prick testing or medically supervised oral food challenge as needed. Primary outcome status was directly determined in 1,917 of 2,130 eligible infants (90.0%), and missing data were addressed with multiple imputation in the intention-to-treat analysis. IgE-mediated egg or peanut allergy occurred in 7.8% of infants in the high-intake group and 8.4% in the standard-diet group (adjusted relative risk [RR], 0.93; 95% confidence interval [CI] 0.69 to 1.26; P=0.65). The per-protocol analysis was concordant, with allergy occurring in 5.6% versus 6.8%, respectively (RR, 0.80; 95% CI, 0.48 to 1.35). Secondary outcomes were also similar between groups. IgE-mediated egg allergy occurred in 6.2% versus 7.2% (adjusted RR, 0.87; 95% CI, 0.62 to 1.21), while peanut allergy occurred in 2.6% of both groups (adjusted RR, 1.02; 95% CI, 0.60 to 1.76). Eczema and allergen sensitization outcomes showed no clear between-group differences. Serious adverse events occurred in 3.6% and 3.8% of participants, respectively (P=0.73), and infant anaphylaxis to egg or peanut occurred in 0.5% and 0.9% (P=0.21). The trial therefore found no evidence that substantially increasing maternal egg and peanut intake during pregnancy and early lactation reduced infant egg or peanut allergy by one year.

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