Caesarean sections, breast feeding, and the microbiome

There is a growing amount of literature on the subject of babies' microbiomes because it is clear that the first few years of life are crucial to the development of the immune system, and poor development can have lasting, life-long consequences.  As we have learned, a healthy microbiome is absolutely critical to a healthy immune system.  Evidence for this connection is vast, but starkly manifests itself in germ-free mice which can not survive long due to autoimmune disease.  So, as the thinking goes, a healthier microbiome as a baby leads to a healthier life.

In any case, a commentary was recently written by AMI Scientific Advisory Board members Maria Gloria Dominguez-Bello, Rob Knight, and a colleague that discusses how delivery mode and infant feeding affect babies' microbiomes.  As it turns out, epidemiological studies on large human populations have correlated Caesarean Section (C-section) delivery to obesity, asthma, celiac disease and type 1 diabetes, which are all autoimmune diseases.  Breast feeding, on the other hand, leads to decreased risk for some of these same diseases.

Research has shown that both C-section and breast feeding have a direct and significant influence on an infant's microbiome.  During vaginal delivery the child's gut is inoculated with the vaginal microbiome, whereas in a C-section the child's gut is associated more with the skin microbiome.  In addtion, breast feeding contains prebiotics that encourage certain bacteria to grow, which selects for a specific infant gut microbiome.  

Interestingly, the authors mention a study that showed the microbiota from the breast milk may actually be different depending on the mode of delivery.  They also comment on a study that showed certain gut bacteria are found in the vaginal microbiomes of pregnant women, as if prepared to inoculate the child.  This is in agreement with another study from Jacques Ravel which I have already blogged about.

It is very important to consider the microbiome when a woman is giving birth and feeding.  If a C-section is required it may be possible to inoculate the child's gut manually, and studies are currently investigating this.  The results of these studies will be the topic of a future blog. 

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