- From birth, the behavior of the gut microbiome plays a role in the development of neurobehaviours in young children.
- However, changes in the microbiome occur long before disorders such as anxiety or depression appear.
- The study also shows that the composition of the gut microbiome affects girls and boys differently.
The gut microbiome, the ecosystem in which microorganisms develop in the human digestive system, not only affects digestive health. Several studies have documented the association between the gut microbiome and the development of behaviors such as depression, anxiety, or attention deficit hyperactivity disorder (ADHD). But to date, there is little or no human data to characterize the role of the microbiome during childhood in relation to these outcomes in children, and how they may differ in boys and girls.
This is now done with this study conducted by Dartmouth University (USA) and published in the journal Pediatric Research.
Much of the previous research focused on participants who already had symptoms of depression or anxiety, Hannah Lau, first author of the study explains. We wanted to look very early on, before these behaviors were expressed, to see if we could determine whether the microbiome affects neurobehaviour, or vice versa. “
The focus on early childhood also allowed researchers to study a critical time window in which the brain may be particularly sensitive to changes in the microbiome.
A link between the microbiome and behavioral development
To determine whether differences in the infant’s microbiome affected neurobehaviour, and whether this behavior varied in boys and girls, the team used a birth cohort study in New Hampshire. Created in 2009, it allows the study of the role of environmental factors in pregnancy and newborn outcomes.
For the study, researchers analyzed stool samples from 260 infants when the babies were six weeks, one and two years old. Thus they were able to describe the types and functions of the microbes present in each participant’s gut. Then they used a tool called the Children’s Behavioral Assessment System, which measures a wide range of clinical and adaptive behaviors in children and young adults to assess their behavioral development.
Differences in the behavior of girls and boys
The researchers found that changes in the microbiome occurred long before behavioral changes. They also found that the microbiomes of infants and young children were closely associated with neurotic behaviors such as anxiety, depression, hyperactivity and social behaviors, in both time- and gender-specific ways.
“For example, we found that greater diversity in the gut was better for boys, which means it was associated with fewer behaviors like anxiety and depression, but not for girls.”Professor Lau explains. According to the researcher, the diversity of microorganisms present in the microbiome can be beneficial for boys, but not for girls. “We also found differences in certain types of bacteria and the essential functions they perform – such as vitamin B synthesis – that were also associated with these findings.”
“We hope the findings will be useful for future studies that can examine some of our specific findings in more depth and clarify whether they can be developed as probiotics or other types of interventions such as promoting milk feeding.”, concludes Hannah Lau.
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