Lactational Changes in Filipino Human Milk Oligosaccharides Reveal Maternal Secretor Status

Breast milk contains Human Milk Oligosaccharides (HMOs), which are the third most abundant solid component and are considered indigestible with no nutritional value to infants. However, HMOs provide protection against pathogens, support gut bacteria, and aid in brain development. This study investigated the relationship between HMOs and secretor status and tracked changes in HMO levels throughout lactation. The study employed a rapid‐throughput extraction method, nano‐HPLC chip/TOF‐MS analysis, and an annotated HMO structure library for oligosaccharide analysis.Results from the study revealed that 81% of Filipino mothers (N = 155) are secretors, while 19% are non‐secretors. The total HMO abundance significantly decreased (p = 0.0001) throughout lactation but was significantly (p = 0.0390) higher in colostrum compared to mature milk. The total fucosylated HMOs had a significantly (p = 0.0460) lower absolute abundance, while the total sialylated HMOs showed a significantly (p = 0.0012) higher abundance in colostrum relative to mature milk. Non‐fucosylated neutral HMOs showed no significant (p = 0.1040) difference in abundance between colostrum and mature milk.This is the first comprehensive data on the maternal secretor status of Filipino mothers, showing the decrease in total HMO abundance throughout lactation and differences in the abundances of various oligosaccharide types between colostrum and mature milk.