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

## TL;DR

This study found that maternal dietary fiber intake during lactation does not affect fucosylation of human milk oligosaccharides, which are important for infant health.

## Contribution

The study is the first to prospectively investigate the association between maternal dietary fiber intake and HMO fucosylation in human milk.

## Key findings

- Maternal dietary fiber intake was not correlated with HMO-bound fucose levels in human milk.
- Secretor mothers and mothers with baby girls showed higher HMO-bound fucose levels.
- Vaginal delivery was associated with lower HMO-bound fucose levels.

## Abstract

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.

Healthy breastfeeding women were recruited within the prospective birth cohort PRIMA. We collected a fresh human milk sample at 1 month postpartum to assess relative human milk oligosaccharide (HMO), HMO‐bound fucose levels, and secretor status. In univariate and multivariate linear regression analysis, we did not observe an association between habitual fiber intake and HMO‐bound fucose levels (both regarded prebiotic in nature) within human milk. Created with BioRender.com.