The gut microbiome (bacteria) is established at birth when bacteria are transferred from mother to baby and then develops during the first year of life as the baby is exposed to different external factors. The diversity and number of bacteria in the microbiota increases over this period to support the development of the immune system.
The types of bacteria found in the initial microbiota reflect whether the baby is born naturally or via caesarean section – vaginal-born babies will have a microbiota that reflects that of their mother, whilst a c-section baby’s microbiome will reflect the environment they are born into. Other factors that can affect the early development of the microbiome include prematurity, hygiene, breastfeeding and antibiotic exposure.
The gut bacteria interact with the immune system and help to promote the growth of immune cells and the normal development of immune function. Improper training of the immune system by the microbiota has been linked to immune-related diseases later in life, so it is important to support the correct development of the bacteria from birth.