Structure-Specific and Individual-Dependent Metabolization of Human Milk Oligosaccharides in Infants: A Longitudinal Birth Cohort Study

To follow human milk oligosaccharide (HMO) biosynthesis and in vivometabolization, mother infant feces from 68 mother–infant dyads at 2, 6, 12 weeks postpartum were analyzed, with 18 major HMOs quantitated. Fucosylated neutral core HMO levels dependent on mothers’ Lewis/Secretor status, whereas most sialylated independent. Infant fecal excretion of gradually declined age, especially for structures. Although decreasing absolute concentrations during lactation, the relative abundance total fucosylated increased both feces. Mono-fucosylated more consumed than those decorated two fucose moieties. More (α2-3)-sialylated degraded (α2-6)-sialylated HMOs. The transition speed metabolization nonspecific or structure-specific consumption stage to complete was individual-dependent. Variation associated mode place delivery, where caesarean section early exposure hospital environment delayed transition.