How baby’s first microbes could be crucial to future health

Altering the community of bacteria that live in the gut might help infants to thrive or even avoid conditions such as asthma and diabetes.

Sarah DeWeerdt, Nature

Within a few weeks of being born, a baby is host to a community of billions of bacteria, viruses and fungi — most of which are found in the gut — that can shape many aspects of health. How that community, or microbiota, assembles is a matter of debate: some researchers have begun to question the dogma that the womb is a sterile environment. Yet it’s clear that birth sets off a radical transformation of the infant gut.

“It’s an incredible ecological event,” says Phillip Tarr, a paediatric gastroenterologist at Washington University in St. Louis, Missouri. Colonization of the gut begins in earnest when a baby encounters microorganisms from its mother’s vagina during birth. As the baby suckles at the breast, it picks up more microbes from its mother’s skin. It also consumes microbes from its mother’s gut that have infiltrated her breast milk.

Later, microbes are picked up from adoring visitors or a lick from the family dog, as well as what Nicholas Embleton, a neonatologist at Newcastle University, UK, refers to as “living in a normal, dirty home environment”. By the age of two or three, the composition of a child’s gut microbiota is very similar to that of an adult’s.

Should the assembly process be derailed, the consequences can be deadly. A considerably altered microbiota has been linked to a form of gut inflammation that is a leading cause of death in infants who are born prematurely. Less extreme changes to the microbiota in otherwise healthy babies might have long-term consequences for health, perhaps playing a part in conditions such as asthma and diabetes.

Researchers are looking for ways to rebalance the microbiota in premature infants. And some are wondering whether it might be possible to reshape the microbial community of the healthy infant gut to help prevent chronic diseases in adulthood.... Read more on Nature