Microbiologist and lead researcher John Penders of Maastricht University (UM) analysed more than 1500 faecal samples from the Berlin children, particularly focusing on babies in the first 31 weeks of life. “This period is crucial for the development of the immune system,” he explains.

“Although there have been previous studies on gut flora in infants, the researchers always looked at a single point in time. But at that age, gut flora is very unstable and still rapidly developing, so we wanted to chart the total development of the gut flora in young children.”

Favourable gut flora is partly determined by a high diversity of bacteria. But how do you know if a small child has such a high diversity? “We found that two factors clearly contribute to the development of favourable gut flora in infants,” Penders says. “First, it makes a difference whether children were born vaginally or through caesarean section. Additionally, the duration of breastfeeding in particular plays a role.”

Diet interventions

In a follow-up study, Penders would like to see whether dietary interventions can improve babies’ intestinal flora and thus reduce their risk of developing allergies.

“We know that children with a non-Western lifestyle, such as in remote areas in Africa and South America, have an intestinal flora with a much higher diversity and more bacteria with anti-inflammatory properties. This is mainly due to their varied and high-fibre diet. Our Western lifestyle and diet depletes our intestinal flora, and this results in a higher risk of allergies. The diet intervention could already take place during pregnancy. We know that children receive a lot of intestinal bacteria from their mothers during birth, and that the anti-inflammatory metabolites can even be transmitted from mother to child before birth.”