PURPOSE OF THE STUDY.
To investigate how maternal dietary egg ingestion during the early postnatal period influences egg protein levels (ovalbumin [OVA]) in breast milk.
Two thousand thirty-four pregnant women were initially screened for eligibility. One hundred and twenty breastfeeding mothers with a history of allergic disease (excluding egg allergy) whose infants were born at ≥36 weeks’ gestation were randomized to modify their diet for egg consumption during their infants’ first 6 weeks of life.
This was a randomized controlled trial in which participants were allocated to 3 groups: high egg consumption (>4 eggs a week), low egg consumption (1–3 eggs a week), or an egg-free group. Baseline data of family history of allergic disease, race, educational level, smoking during pregnancy, pets in the home, and egg intake were collected. Nonblinded participants recorded egg intake prospectively. OVA levels were measured in breast milk and collected at 2, 4, and 6 weeks of lactation. Infant blood samples measuring serum egg-specific IgE and IgG4 were collected at 6 and 16 weeks. All data were obtained prior to egg introduction to the infant.
One hundred and twenty women were randomized: 40 to high-egg, 44 to low-egg, and 36 to egg-free diets. No significant differences were found in baseline characteristics between the groups. One hundred and nine women completed the 6-week intervention. Compliance was 100% (36 of 36 women) in the high-egg group, 95% (40 of 42 women) in the low-egg group, and 23% (7 of 31 women) in the egg-free group. Women in the high-egg group had significantly higher breast milk OVA concentrations than women on an egg-free diet (P = .036), but no detectable difference in OVA was seen between the low-egg and egg-free groups at 2, 4, or 6 weeks. One-third of the women did not have detectable breast milk OVA concentrations at any time during the study. Infant egg IgG4 levels were positively associated with average maternal egg ingestion. Each additional egg per week was associated with a 22% increase in infant IgG4 levels.
Increased maternal egg consumption is associated with more OVA in breast milk and increased serum IgG4 levels in infants, reflecting possible oral tolerance development in breastfed babies.
Recent studies have demonstrated that sensitization and clinical reactions to eggs can occur early in susceptible individuals, often with reactions occurring at the first exposure to egg. Like the LEAP study for peanut, it would be helpful to be able to use early introduction of egg to promote the development of oral tolerance instead of food allergy. This is the first randomized controlled study to show that increasing amounts of egg in a maternal diet are associated with more egg in breast milk. Infant IgG4 levels also increase proportionally, possibly supporting the development of early oral tolerance.
- Copyright © 2017 by the American Academy of Pediatrics