A new study led by scholars at the University of Minnesota has found hundreds of components of human milk are determined by genetic differences in women, which have implications for infants’ nutritional health.
The study authors examined the relationships between maternal genetics, milk gene expression, milk composition, and the infant fecal microbiome of 310 exclusively breastfeeding mother-infant pairs. In their analysis, the researchers identified nearly 500 genetic loci associated with milk gene expression unique to the lactating mammary gland. Many of these genes were found to be connected to infant gut microbiome, such as the expression of inflammation-related genes with the milk interleukin-6 protein (IL-6). Infants consuming milk high in IL-6 had lower abundances of two types of beneficial bacteria in their digestive tracts.
According to the authors, maternal health research has been historically underrepresented in the field of human genetics due to logistical and ethical implications for performing randomized trials on infant nutrition. However, breast milk presents an easily obtained and non-invasive biospecimen that could help to advance maternal genetic research. The authors believe their findings provide evidence that leveraging modern human genomic techniques can further our understanding of both infant and maternal health.
Alongside scholars at the University of Minnesota, the research team included authors from the University of California, San Diego, the University of Oklahoma Health Sciences Center, and the University of Chicago.