Human milk oligosaccharides (HMOs) are the third most abundant component in human milk. However, each mother produces her own fingerprint of HMOs. Maternal factors that act as drivers of HMO composition include genetics (secretory vs non-secretory, Lewis gene, other), epigenetics, environment (diet, lifestyle (exercise), exposures (smoking)), health and disease as well as parity.
Due to the HMOs properties, it interfaces with the host microbe interactions. These interactions are potentially beneficial like being antimicrobials against Group B Streptococcus and being an antiadhesive to prevent pathogens from attaching to the epithelial layer. Sometimes individual HMO are effective whilst other times comply mixtures of HMOs are required.