A new study from Applied and Environmental Microbiology has successfully determined that it is the sugar, and not the protein, components in mother’s milk that are the growth substrates for gut bacteria colonization


Milk plays an important role in a baby’s diet, providing essential nourishment.  It has recently been discovered that milk glycoproteins, milk proteins with sugar molecules, serve as important growth substrates for the gut microbiota, including bifidobacteria, in nursing infants. Gut microbiota are important for proper digestion and for a strong immune system. Nursing ensures that children receive the proper nutrients needed for proper development of microbiota in the gut. It is well known that milk provides the proper substrates needed for microbiota growth, but researchers have not been clear on what exact component of milk is responsible for this growth induction.

In a new study published in Applied and Environmental Microbiology, researchers proposed to find out whether it is the sugar component (ie. the glycans), or the protein component (ie. the polypeptides) of milk, which were responsible for the growth of bifidobacteria in the guts of newborns.

In this study, researchers used the EndoBI-1 enzyme to remove the glycans from the milk glycoproteins and tested their consumption by various bifidobacteria. Researchers measured the growth of the bifidobacteria infantis subspecies, a species that grows well on human milk sugars, and the bifidobacteria lactis subspecies, a species that does not grow well on human milk sugars.

The results indicated that, in comparison to bifidobacteria lactis, the bifidobacteria infantis showed a greater ability to consume the released glycans. These results prove that it is the glycans, and not polypeptides, which stimulate the growth of the bifidobacteria and serve as better growth substrates for gut bacteria than intact milk glycoproteins. These results could be used in the development of more effective and nutrient-rich formulas for infants, in order to promote healthier and more-stable microbiota colonization of the gut.




Written By: Mariana Nikolova, BSc

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