Gut Microbiota

Before birth, the microbiota does not exist, as the body is sterile. (1, 6) The establishment of the microbiota does not develop until birth. (5) The first factor that affects the composition of the gut microbiota is the mode of delivery. (3, 5) Babies that are delivered vaginally have microbiota similar to that of the mother’s vaginal and fecal microbiota. In comparison, babies delivered by caesarean section have microbiota similar to the mother’s skin microbiota. Although the maternal bacterial communities are well differentiated, it has been shown that the newborn microbiota are undifferentiated in either mode of delivery. (1, 3) The second factor to influence the microbiota is whether the infant is fed with breast milk or formula. (1, 6) Breast milk results in microbiota dominated by bifidobacteria whereas formula results in higher amounts of Escherichia coli (E. coli), Clostridium difficile (C. difficile), Bacteroides fragilis (B. fragilis) and lactobacilli.
(1, 2, 5) Other feeding habits after weaning can also have an affect on the microbiota. Long-term diets rich in animal protein and fat have been shown to have microbiota dominated by Bacteroidetes, in comparison to high-fibre diets, which are dominated by Prevotella. (2, 5) Although there is evidence suggesting that diet affects the microbiota, the causal methods are not yet fully understood. (5) Genetics is another contributing factor but it is also one that cannot be as easily modified as the