Maternal Egg and Peanut Diet Does Not Reduce Infant Allergy Risk

Eating a diet rich in eggs and peanuts during pregnancy and breastfeeding does not lower the risk of food allergies in high-risk infants by age one, according to a randomized clinical trial published September 17, 2026, in the New England Journal of Medicine.

Researchers evaluated whether exposing unborn and nursing infants to high levels of egg and peanut proteins could induce early immune tolerance before children start eating solid foods. Investigators tracked 2,137 pregnant women whose unborn children had at least two biological family members with medically diagnosed allergic disease, such as asthma, eczema, allergic rhinitis, or IgE-mediated food allergy. Participants were enrolled before 23 weeks of gestation across clinical sites in Adelaide, Melbourne, Perth, and Sydney, Australia, according to study documentation.

The trial assigned participants in a 1-to-1 ratio to follow either a high-intake diet or a standard diet. The high egg-peanut group consumed at least 6 eggs and 60 peanuts per week from enrollment until four months postnatally during lactation. The standard-diet group consumed no more than 3 eggs and 30 peanuts per week, aligning with standard nutritional patterns during pregnancy and lactation.

Out of 1,070 participants assigned to the high intake group and 1,067 assigned to the standard diet group, researchers found no significant difference in allergy rates at one year of age. IgE-mediated egg or peanut allergies developed in 83 of 1,066 infants, or 7.8 percent, in the maternal high egg-peanut group. In the standard-diet group, 89 of 1,064 infants, or 8.4 percent, developed these allergies, yielding a relative risk of 0.93 with a 95 percent confidence interval ranging from 0.69 to 1.26.

Understanding Early Immune Development

Immune responses leading to food allergies often establish early in life, sometimes before infants consume solid foods. Previous work by the trial authors noted that egg-specific immune responses can appear by four months of age in susceptible infants, and early introduction of eggs into solid foods at four to six months does not alter those responses. This timing prompted the trial hypothesis that tolerance pathways might require stimulation earlier during pregnancy and lactation.

During pregnancy, the fetal immune system encounters maternal antigens via amniotic fluid. Breast milk provides subsequent exposure after birth and has demonstrated tolerance-inducing properties in animal models. Prior observational studies suggested a link between higher maternal consumption of peanuts and tree nuts and lower childhood peanut and tree nut allergy risk, but robust randomized trial evidence regarding maternal dietary intervention remained scarce until now.

Trial Design and Safety Findings

The trial targeted a 30 percent reduction in allergy prevalence, assuming a baseline allergy rate of 16 percent in this high-risk population. Pregnant women with personal egg or peanut allergies were excluded from participation to ensure dietary safety. Safety measures remained similar between both study arms throughout the intervention period.

Funding for the study was provided by the Australian National Health and Medical Research Council and other institutional supporters. The trial was registered under the Australian New Zealand Clinical Trial Registry with the identifier ACTRN12618000937213.