This highlights the pivotal role that the mother's gut microbiome has in fostering a baby's gut health.

Bifidobacterium in general are known for being one of the first colonizers of the infant gut. This is because of their important role degrading carbohydrates from the diet that the infant gut cannot digest.

This has a positive effect not only on the development of the gut but also the baby's immune system. The mechanism for this is quite complex but in general terms Bifidobacterium have been shown to interact with human immune cells and to modify immune responses.

The human microbiome changes constantly and Bifidobacterium is a good example of this. The amount of Bifidobacterium in our gut changes during our lifespan as does the composition of specific Bifidobacterium species in response to our diet.

Bifidobacterium is the most abundant bacteria in the first months of life when a baby is breastfed and when microbial diversity  is still very low. The microbiota begins to change when solid food is introduced and we have less Bifidobacterium as we get older when the microbial diversity in our gut increases.

Species such as Bifidobacterium adolescentis and Bifidobacterium longum are typically associated with adulthood due to their ability to degrade plant-derived carbohydrates found in fruit and vegetables. But B breve and certain other species are generally associated with infancy.

Human milk is a complex fluid capable of satisfying all the nutritional requirements of a newborn. It also provides extensive health benefits such as reduced risk of various infections. Its composition changes over the period of lactation adapting to the requirements of the infant.

Breast milk is one of the main factors that influences the infant microbiota as breastfeeding increases the number of Bifidobacterium in the infant gut.

One specific component of breast milk that affects the composition of the microbiome is human milk oligosaccharides which are the most abundant carbohydrates present in breast milk after lactose.

These carbohydrates cannot be digested by the human gut which is where B breve plays an important role. It's among the microbes that can degrade human milk oligosaccharides and in this way they promote its persistence in the gut.

Source: https://medicalxpress.com/news/2024-03-gut-microbiome-bifidobacterium-breve-babies.html