Plenary Session - The Human Milk Microbiome: Using Space Science Technology to Better Understand the Association of Milk Microbiota with Breastfeeding Practices and Infant Growth at Different Stages of Lactation

Breast milk composition has an intimate association with infant growth and can be critical for long-term health. While evidence has shown that breast milk microbiota can directly seed the infant gut microbiome, information relevant to milk bacterial community development during the different stages of lactation and maternal demographics, anthropometrics, and dietary habits is limited particularly in LMIC as mothers from high income countries populate the vast majority of human milk microbiome studies.

Here we will present how high-resolution microbiome technology developed in the space sciences was used to study the microbiome of Mam-Mayan mothers living in eight remote rural communities in the Western Highlands of Guatemala, where nearly all mothers comply with World Health Organization's recommendation to breastfeed for six months. We observed changes in milk bacteria over the first 6 months of lactation that was associated with maternal and infant characteristics. Milk bacterial communities were associated with maternal factors. Higher microbial diversity was supported by having a healthy BMI, the absence of subclinical mastitis and by breastfeeding practices. Exclusive breastfeeding was associated with more differentially abundant bacteria, including commensal and lactic acid bacteria whereas the addition of agüitas (herbal teas) and/or complementary foods introduced more environmentally sourced bacteria to the milk microbiome ecosystem. Findings show possible associations of the milk microbiome with infant weight, length and head circumference in breastfed infants < 6 months of age. In conclusion, the milk microbiome ecosystem is a dynamically changing ecosystem that requires further investigation given its association with maternal and infant health.