Human Milk Oligosaccharides and Infant Neurodevelopment: A Narrative Review

The objective of this narrative review was to synthesize the literature on human milk oligosaccharides (HMOs) and neurodevelopmental outcomes in human milk-fed infants. We conducted a scoping review of the literature indexed in PubMed reporting observational or interventional studies on HMO exposure in relation to psychometric measures in infants. Studies were characterized based on study design and definitions of HMO exposure and neurodevelopmental outcomes. Six studies were identified; all were observational in design, and five were conducted in full-term infants. Sample sizes ranged from 35-659 infants. HMOs were defined as individual concentrations or relative abundances assessed at 1 and/or 6 months of age. Studies accounted for differences in HMO exposure based on maternal secretor status. Neurodevelopmental outcomes were assessed between 6 and 24 months of age and included four domains. Studies in full-term infants reported that total and individual fucosylated and sialylated HMOs were positively associated with cognitive, language, and motor skill domains between 18 and 24 months of age, while the single study in preterm infants reported no statistically significant findings in the full cohort. The presence of a maternal secretor did not consistently alter the associations between HMO exposure and neurodevelopmental outcomes. Emerging evidence from observational studies suggests that HMO exposure may be beneficial for neurodevelopment in infants.