Maternal obesity may elevate bile acids in breast milk

Maternal obesity appears to increase bile acid (BA) levels in breast milk, which may have implications for neonatal digestion, maturation, and health.

A group of researchers analysed BA profiles in breast milk and plasma in lactating mothers with or without obesity across two independent clinical cohorts. They collected breast milk and plasma samples from breastfeeding women classified as normal weight or with obesity. Reverse phase liquid chromatography plus tandem mass spectrometry (LC-MS/MS) was used to quantify BA concentrations.

BAs were found in breast milk, primarily as glyco- and tauro-conjugated of the primary BAs cholic (CA) and chenodeoxycholic acid (CDCA), but at lower levels than in plasma under normal-weight conditions.

Maternal obesity contributed to a significant increase in total breast milk BA levels, whereas BA concentrations and composition remained unchanged. Furthermore, BA levels in breast milk showed a positive association with maternal prepregnancy BMI, circulating leptin (a marker of adiposity), and insulin levels.

“Further research is warranted to elucidate the impact of these alterations on infant health and development,” the researchers said.

Breast milk provides essential nutrients and bioactive molecules necessary for infant growth and development. However, “accumulating evidence from our group and others indicates that maternal factors, such as obesity, can alter breast milk composition,” according to the researchers.

“BA, both primary and secondary, have been identified in human breast milk, but the precise composition and their role ... remain largely underexplored,” they added.