Transition from milk-based diet to family food impacts Infants’ gut bacteria

It is the transition to eating the family's food and not the weight of the mother that has the greatest impact on the composition of gut bacteria in nine-month-old children. This is one of the findings from a study from the National Food Institute, Technical University of Denmark, and the University of Copenhagen. Knowledge about how gut bacterial composition is established in early childhood may help to understand its significance in relation to diseases later in life.

Infants are born virtually without bacteria in their gut. Since a good composition of gut bacteria is important for the immune system and a healthy digestive system, it is interesting to identify the factors that affect the gut bacteria in children's first years of life.

The composition of a person's gut bacteria is affected by their diet and has repeatedly been associated with obesity. However, it is not known whether an infant's gut bacteria are affected either by their mother's weight or by the transition from a milk-based diet to family food.

Mapping out bacterial development

A study from the National Food Institute and University of Copenhagen has increased our knowledge of these interactions through analyses of stool samples from more than 200 Danish children, half of which are born to mothers of normal weight and half to obese mothers.

The samples have been collected at nine and 18 months of age, during the time where the children's diet changes from formula/breastfeeding to the food that the rest of the family eats. By mapping the bacterial composition in the gut at these two stages the researchers have shown that bacterial composition has developed remarkably similar among children in both groups.

"The study shows that the development in bacterial composition between nine and 18 months is evidently independent of maternal overweight and of the associated eating habits. The development is primarily affected by the milk-based diet being replaced with family food, which is rich in fibre and protein, as well as breastfeeding duration," Professor at the National Food Institute Tine Rask Licht says.

Knowledge can lead to healthier bacterial composition

While other factors such as mode of delivery, gestational age at birth and the mother's weight may have influenced the development of gut bacterial composition immediately after birth, the study shows that these factors have very little influence on bacterial composition by the time infants are nine months old.

"It takes three to five years before a child's gut bacterial population is fully established. The more we know about the factors that influence development at different stages, the better we can support initiatives that can be used to help children develop a healthy gut," Tine Rask Licht explains.

"Knowledge about how gut bacteria are established in early childhood can help shed light on why some people end up struggling with their weight as well as diseases like allergies and diabetes later in life," she adds.