Human milk oligosaccharide secretion dynamics during breastfeeding and its antimicrobial role: A systematic review.

Background: Human milk oligosaccharides (HMOs) are bioactive components of breast milk with diverse health benefits, including shaping the gut microbiota, modulating the immune system, and protecting against infections. HMOs exhibit dynamic secretion patterns during lactation, influenced by maternal genetics and environmental factors. Their direct and indirect antimicrobial properties have garnered significant research interest. However, a comprehensive understanding of the secretion dynamics of HMOs and their correlation with antimicrobial efficacy remains underexplored.

Aim: To synthesize current evidence on the secretion dynamics of HMOs during lactation and evaluate their antimicrobial roles against bacterial, viral, and protozoal pathogens.

Methods: A systematic search of PubMed, Scopus, Web of Science, and Cochrane Library focused on studies investigating natural and synthetic HMOs, their secretion dynamics, and antimicrobial properties. Studies involving human, animal, and in vitro models were included. Data on HMO composition, temporal secretion patterns, and mechanisms of antimicrobial action were extracted. Quality assessment was performed using validated tools appropriate for study design.

Results: A total of 44 studies were included, encompassing human, animal, and in vitro research. HMOs exhibited dynamic secretion patterns, with 2'-fucosyllactose (2'-FL) and lacto-N-tetraose peaking in early lactation and declining over time, while 3-fucosyllactose (3-FL) increased during later stages. HMOs demonstrated significant antimicrobial properties through pathogen adhesion inhibition, biofilm disruption, and enzymatic activity impairment. Synthetic HMOs, including bioengineered 2'-FL and 3-FL, were structurally and functionally comparable to natural HMOs, effectively inhibiting pathogens such as Pseudomonas aeruginosa, Escherichia coli, and Campylobacter jejuni. Additionally, HMOs exhibited synergistic effects with antibiotics, enhancing their efficacy against resistant pathogens.

Conclusion: HMOs are vital in antimicrobial defense, supporting infant health by targeting various pathogens. Both natural and synthetic HMOs hold significant potential for therapeutic applications, particularly in infant nutrition and as adjuncts to antibiotics. Further research, including clinical trials, is essential to address gaps in knowledge, validate findings, and explore the broader applicability of HMOs in improving maternal and neonatal health.