Composition of human milk – a journey of discovery

Key findings

Human milk is more than nutrition. Multifunctional proteins including sIgA, lactoferrin and lysozyme, as well as free fatty acids, act as anti-infective agents supporting infant health.

These agents work together to inactivate, destroy or bind to specific microbes, preventing their attachment to mucosal surfaces.

Living maternal cells are transferred through the milk to the infant. These include blood-derived leukocytes, cells of the mammary epithelium, stem cells and cell fragments, which provide immune-protection to the infant.

A large number of human milk oligossaccharides are also transferred to the infant and have been reported to have an important immunological function acting as probiotics that promote the intestinal growth of commensal bacteria. They also act as decoys or receptor analogues to inhibit the binding of pathogens, – including rotaviruses – to intestinal surfaces.

Human milk also contains commensal bacteria that become part of the gut microflora and influence inflammatory and immunomodulary processes. Not only do commensal bacteria prevent overgrowth of pathogenic bacteria, they also acidify the gut, ferment lactose, breakdown lipids and proteins, and produce vitamins K and biotin.

Download the infographic here: "What makes breastmilk so unique?"