03 October 2014 - The Conversation - Babies' gut bacteria are mostly fixed by time spent in the womb

Once the food is mechanically reduced through chewing, bacterial communities in the gut get to work. Right from birth, these have been cultured for specific tasks: some love fats while others prefer complex proteins. It is only through having a range of bacterial species each with their preferred niche that the gut can form manageable nutrients and can synthesise vitamins and enzymes for proper digestion.

And gut bacteria’s function is not limited to just digestion. For example, gut bacteria can communicate with the brain and even prepare body’s defences.

Their function is so important that these gut bacteria can be considered an organ in their own right, one that performs enzymatic food degradation to which, until recently, we have been oblivious. These gut bacteria have been shown to influence emerging lifestyle diseases such as cancer, heart disease and diabetes, other research has also found links in composition of gut bacteria in obese and lean subjects.

The key to all of these is the healthy development of the gut. This development occurs during the pregnancy period but continues after birth and is integral in the absorption of nutrients as well as development of the immune system. The gut development starts to increase at a rapid rate in the final two months of pregnancy, which means that infants born prematurely are exposing an underdeveloped gut to the environment.

Now, a new study published in the journal Proceedings of the National Academy of Sciences has added a critical piece to the puzzle. Researchers at Washington University show that even though we are exposed to a wide range of bacterial species from the environment, our gut bacteria don’t change very much later in life. The main criteria that determines the constituent bacteria of the gut are decided by how long baby remained in the womb.