What do those terrible twos have to do with gut bacteria? More than parents may think, say researchers from Ohio State University. They analyzed stool samples from more than 75 children ages 18 to 27 months and compared them to parent-answered questionnaires about emotional reaction. What they found was that variations in bacterial diversity were strongly linked to differences in behavior and temperament—most notably among boys.
Toddlers whose gut microbes were more diverse were more likely to be curious, social, and happy, while fewer types and numbers of bacteria was associated with signs of stress and fearful behavior, according to findings published in the journal Brain, Behavior and Immunity. This may have something to do with the relationship between gut flora and stress hormones, say researchers, which can affect both physical and mental health.
“There is substantial evidence that intestinal bacteria interact with stress hormones—the same hormones that have been implicated in chronic illnesses like obesity and asthma,” said study author Lisa Christian. “A toddler’s temperament gives us a good idea of how they react to stress. This information combined with an analysis of their gut microbiome could ultimately help us identify opportunities to prevent chronic health issues earlier.”
Interestingly, the connection between gut bacteria and temperament remained despite factors such as diet, breastfeeding, or how the child was delivered (either vaginally or by C-section)—and that connection was found to be more consistent among males than females. Researchers plan to continue studying the link between gut bacteria and behavior, but their findings are in line with previous studies showing a strong gut-brain connection.