Breast milk is crucial in the development of late-onset breast milk jaundice (BMJ), possibly due to the composition of breast milk and the lactating mother’s diet. To explore the possible nutritional pathogenesis of late-onset BMJ, we investigated the lactation diet and collected breast milk by following the 42-day postpartum mother−infants pairs in Beijing and a total of 94 pairs were enrolled. The macronutrient content of breast milk was measured, and the epidermal growth factor (EGF) content in breast milk was determined by ELISA. Data on in-hospital and out-of-hospital breastfeeding, infant growth, jaundice-related vaccination, and puerperium diet were collected. The BMJ group received the second dose of hepatitis B vaccine later than the control group, and the difference was statistically significant (p < 0.001). The EGF concentration in breast milk was lower in the BMJ group than in the control group (p = 0.03). When EGF increased by 1 ng/mL, the transcutaneous bilirubin (TcB) value decreased by 0.33 ng/mL and 0.27 ng/mL before and after the adjustment, respectively. A 1 g increase in oil intake led to a 0.38 ng/mL increase in EGF concentration before the adjustment. With a 1 g increase in oil intake, the TcB value decreased by 0.27 ng/mL before the adjustment, and with a 1 g increase in soybean and soybean product intake, the TcB value decreased by 0.34 ng/mL after the adjustment. Collectively, EGF in breast milk may inhibit the occurrence of late-onset BMJ, and the dietary intake of oil in lactating mothers may affect the level of EGF in breast milk, thus affecting the occurrence of late-onset BMJ. Finally, dietary oil intake may be a protective factor for the occurrence of late-onset BMJ by increasing EGF levels in breast milk.
Keywords: breast milk; epidermal growth factor; late-onset breast milk jaundice; postpartum diet.