The human milk microbiome: Who, what, when, where, why, and how?

Abstract

Human milk (HM) contains an incredible array of microorganisms. These likely contribute to the seeding of the infant gastrointestinal microbiome, thereby influencing infant immune and metabolic development and later-life health. Given the importance of the HM microbiota in this context, there has been an increase in research efforts to characterize this in different populations and in relation to different maternal and infant characteristics. However, despite a decade of intensive research, there remain several unanswered questions in this field. In this review, the "5 W+H"approach (who, what, when, where, why, and how) is used to comprehensively describe the composition, function, and origi..