Gut microbiota in caesarean-born babies catches up

Infants born by caesarean section have a relatively meagre array of bacteria in the gut, but by the age of three to five years they are broadly in line with their peers. This is according to a study by Swedish researchers, which also shows that it takes a remarkably long time for the mature intestinal microbiota to get established.

The research was headed by Professor Fredrik Bäckhed and his team from the University of Gothenburg, who had previously demonstrated that the composition of children’s intestinal microbiota is affected by their mode of delivery and diet. In the current study, the researchers examined in detail how the composition of intestinal bacteria in 471 children born at Hallands Hospital Halmstad had developed.

The first faecal sample was collected when each child was a newborn infant; thereafter, sampling took place at four months, 12 months, three years and five years. The scientists were thus able to follow the successive incorporation of various bacteria into the children’s gut microbiota, with the results published in the journal Cell Host & Microbe.

At birth, the infant’s intestine has already been colonised by bacteria and other microorganisms. During the first few years of life, the richness of species steadily increases. What is now emerging is that the intestinal microbiota forms an ecosystem that takes a long time to mature. Even at five years of age, the system is incomplete. The maturation process can look very different from one child to another, and take varying lengths of time.

At the age of four months, the gut microbiota in the caesarean-born infants was less diverse compared with vaginally born infants. However, when the children were three and five years the microbiota diversity and composition had caught up and were largely normalised intestinal microbiota.

“Our findings show that the gut microbiota is a dynamic organ, and future studies will have to show whether the early differences can affect the caesarean children later in life,” Prof Bäckhed said.

“It’s striking that even at the age of five years, several of the bacteria that are important components of the intestinal microbiota in adults are missing in the children,” he added. This indicates that the intestine is a complex and dynamic environment where bacteria create conditions for one another’s colonisation.

According to the researchers, the study has broadened our understanding of how humans interact with the trillions of bacteria contained in our bodies, and of how these bacteria become established. Gothenberg researcher Lisa Olsson, a co-first author on the study, noted, “Children learn skills like walking and talking at different rates, and it turns out that the same applies to the maturity of the gut microbiota.”

Prof Bäckhed concluded, “By investigating and understanding how the intestinal microbiota develops in healthy children, we may get a reference point to explore if the microbiota may contribute to disease in future studies.”

Image credit: ©stock.adobe.com/au/Monkey Business Images

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