Maternal Dietary Fiber Intake During Lactation and Human Milk Oligosaccharide Fucosylation: a PRIMA Birth Cohort Study.

Human milk oligosaccharides (HMOs) have an important role in the microbiome and immune system development of breastfed infants. Previous explorative studies indicated an association between maternal carbohydrate intake, including dietary fibers, and specific fucosylated HMOs in human milk (HM). Here, we aim to test whether the intake of dietary fibers by breastfeeding mothers is associated with the level of HMO-bound fucose in HM samples within a prospective birth cohort study. We assessed dietary fiber intake of healthy mothers (n = 164). HMO levels were semi-quantified in HM samples collected at 1 month postpartum. We found no correlation between fiber intake and HMO-bound fucose levels. However, secretor mothers (β = 2.22, p < 0.001) and mothers with a baby girl showed a positive correlation (β = 0.41, p = 0.016) with the level of HMO-bound fucose. In contrast, vaginal delivery negatively correlated with the level of HMO-bound fucose (β = -4.93, p = 0.008). Overall, there was no association between maternal fiber intake and HMO-bound fucose levels. Delivery mode, secretor status, and infant sex emerged as the dominant factors associated with HMO fucosylation in HM. Future research should investigate mechanisms underlying HMO fucosylation and its relevance for infant's health.