top of page
  • Dr. Lauren LeMay-Nedjelski

What’s in human milk?: Exploring the role of oligosaccharides

Updated: Apr 13, 2022

Many microorganisms are found in human milk, including beneficial bacteria. These bacteria make up what is known as the human milk microbiota. The milk microbiota may play a vital role in the healthy development of the infant gastrointestinal tract and may be associated with short- and long-term health outcomes. In addition to these bacteria, human milk is also a rich source of prebiotic fibres called oligosaccharides. When ingested by the infant, oligosaccharides serve as a food source for the bacteria in the infant gut. However, it is unknown whether oligosaccharides and bacteria interact within human milk. Therefore, research is continuing to ascertain whether maternal health is associated with the unique composition of oligosaccharides in human milk.

In work led by one of our former PhD students, Dr. Lauren LeMay-Nedjelski, we strived to determine if there was an association between the milk microbiota and oligosaccharides in human milk. We also aimed to establish whether maternal factors (e.g., race, gestational diabetes and body mass index [BMI]) and obstetrical factors (i.e., Caesarean [C]-section) were associated with the oligosaccharides found in human milk.


You can read the study published in the Journal of Nutrition here:


Study Findings

We analyzed the microbiota composition and oligosaccharides in 107 milk samples obtained from mothers of term infants at three months post-partum. We found several associations between specific bacteria and oligosaccharides in the human milk samples. Pre-pregnancy BMI, maternal race, and breastfeeding frequency were associated with the oligosaccharide composition of human milk. Interestingly, gestational diabetes was not associated with the oligosaccharide composition of human milk.

What does this mean?

Our work shows that maternal factors are associated with the composition of human milk, including the microbiota and oligosaccharides. Importantly, our results cannot yet determine whether these associations are the cause or effect of maternal factors. We also don't know if the observed associations are positive or negative for the mother or infant. Further research is needed to investigate the role both the milk microbiota and oligosaccharides play in maternal and infant health.

What's next?

Our lab continues to investigate the role of the milk microbiota and oligosaccharides in both infant and maternal health. New studies are in the development stages. Stay tuned!


This research was supported by the Canadian Institutes of Health Research (CIHR) and Diabetes Canada. Dr. LeMay-Nedjelski was also supported by a CIHR Doctoral Award.


bottom of page