Breast milk is the optimal food for babies and in most cases, should be their exclusive form of nourishment for the first 6 months of life. Human milk oligosaccharides (HMOs) are among the many highly evolved advantages of human milk. HMOs are complex carbohydrates of which over 200 different forms have now been described and they form the major constituents of human milk; a condition that is unique to humans.
HMOs have many functions including acting as decoys against pathogenic bacteria, improving intestinal health and contributing to brain development. There is a wide diversity of HMOs among different mothers that is controlled in part by genetic factors.

In collaboration with co-workers at the University of California at Davis, we have published a proof-of-principle study using breast-milk and stool samples from rural Gambian mothers around MRC Unit The Gambia’s Keneba Field Station and matched the HMO analysis in milk with the infants’ gut microbiome, their growth and infection patterns. We found that mothers nursing in the wet season (July to October) produced significantly lower levels of oligosaccharides compared to those nursing in the dry season (November to June). We also showed that specific types and structures of HMOs are sensitive to environmental conditions, protective of morbidity, predictive of growth, and correlated with specific microbiota.These findings highlight the importance of breast milk derived from HMOs for infant health.

This study is part of the ENID trial supported by the UK Medical Research Council (MRC) and the UK Department for International Development (DFID) under the MRC/DFID Concordat agreement. The ENID-Bioactives sub-study was supported by a Grand Challenges Explorations award from the Bill and Melinda Gates Foundation. Additional funding came from the UK MRC programme supported by a postdoctoral fellowship from the Alfred P. Sloan Foundation Microbiology of the Built Environment program and the National Institutes of Health Awards and the Peter J. Shields Endowed Chair in Dairy Food Science.

Acknowledgement
We thank the women of West Kiang who participated in the study. We acknowledge the enthusiastic work of the ENID and ENID-Bioactives study teams, especially MRCG staff.

Authors
Jasmine C. C. Davis, Zachery T. Lewis, Sridevi Krishnan, Robin M. Bernstein, Sophie E. Moore, Andrew M. Prentice, David A. Mills, Carlito B. Lebrilla, Angela M. Zivkovic

Read more about the study on the Scientific Reports website.
http://www.nature.com/articles/srep40466