Insulin levels could affect breast milk production in new mothers

The sensitivity to insulin of the human mammary gland could affect the ability to produce breast milk in new mothers, according to new research. Scientists at the Cincinnati Children's Hospital and the University of California Davis have added to their previous research, suggesting that during lactation, insulin can affect breast milk production.

As well as detailing the increase in mammary gland sensitivity, the research also covers the way in which certain genes become 'switched on' during the process of human lactation. In order to get this insight, researchers utilised next generation sequencing technology - RNA sequencing - to provide details on the process of milk production within the human mammary gland. The RNA sequencing was able to provide "exquisite details" as to exactly how milk is produced, according to Doctor Laurie Nommsen-Rivers, a scientist at the hospital and corresponding author of the study.

The previous research undertaken into the processes of human milk production showed that some mothers have suboptimal glucose metabolism markers. Women that are at an advanced maternal age, have a baby with a high birth weight, or are overweight are more likely to find that their initial milk production is slow due to these markers, suggesting that insulin plays a role in the function of the mammary gland.     

Whilst previously it was believed that insulin had no role in the regulation of the cells that produce milk within the human breast as these cells do not absorb sugars, the new research has found that insulin has more functions within the human body than just facilitating the uptake of sugars. The use of RNA sequencing revealed that the milk-making cells in the mammary gland express a sensitive number of genes.

These genes switch on and off depending on the levels of immunity-boosting colostrum required at different stages of milk production. The PTPRF gene in particular may be a biomarker of the effects of insulin resistance upon low milk supply as it tends to be triggered by insulin binding to a cell surface receptor.

The researchers are now intending to perform a Phase I/II clinical trial to see if a blood sugar control drug - usually used by type 2 diabetes sufferers - can affect the levels of milk produced in the human mammary gland.