Effect of cooked and raw egg consumption on ovalbumin content of human milk: A randomized, double-blind, cross-over trial

Background: Maternal avoidance of egg intake has been recommended to treat egg allergy in breastfed infants. Objective: To determine if the concentration of ovalbumin (OVA) in human milk is directly related to the quantity and form of egg consumed by breastfeeding mothers. Methods: Randomized, blinded, cross-over, intervention trial. Breastfeeding women (n = 41) attended four clinic days between 11 and 14 weeks of lactation and on each day were randomly allocated to receive a test breakfast, identical except for the egg content (no egg, one raw egg, half a cooked egg or one cooked egg). Breast milk samples were collected at two hourly intervals for 8 h and their OVA concentration measured by ELISA. Results: There was a direct, dose-response between the amount of cooked egg ingested and the peak OVA concentration (no egg 0.05ng/mL [95% confidence interval (CI), 0.01-0.11], half a cooked egg 2.24 ng/mL [95% CI, 0.57-3.91], one cooked egg 3.16 ng/mL [95% CI, 1.41-4.91], n = 41, P < 0.05) as well as the total OVA excretion (no egg 0.18 ng/mL/h [95% CI, 0.04-0.39], half a cooked egg 4.93 ng/mL/h [95% CI, 1.40-8.46], one cooked egg 9.14 ng/mL/h [95% CI, 4.25-14.03], n = 41, P < 0.05). The peak concentration and total OVA excretion in response to one raw egg did not differ from ingesting half a cooked egg. There was no detectable OVA in the breast milk of 24% (10/41) women up to 8 h after any egg challenge. Conclusion: OVA was detected in the breast milk of lactating women up to 8 h after a controlled intake of egg. A dose-response correlation was indicated. As excretion of OVA in human milk appears to be a normal phenomenon, further studies need to determine the threshold of OVA excretion that leads to symptoms in egg-allergic breastfed infants.