A new study was recently published that highlights the gut-brain axis once again. The study, out of Ohio State University and published in Brain, Behavior, and Immunity, compares the microbiomes of toddlers and compares it to their overall behaviors. The results show an association between temperament and the microbiome may exist.

In the study 77 toddlers were recruited to take food questionnaires, behavioral tests, and have their stools sampled. They discovered that certain microbiome differences, which were not attributable to differences in diet, were directly associated with behavioral traits. Chief among them was the discovery that higher microbiome diversity was correlated to more extraversion in children. Whether or not this microbiome difference is the cause, or an effect, of these children being more active and engaged with their environments is still unknown. Another connection was that Rickenellaceae was associated with fearful female toddlers and high intensity male toddlers. This was interesting because bacteria from this genus have been associated with depression.

We note that the researchers’ testing methods were hardly rigorous due to the lack of controls, but the gut-brain axis has been well established, so this work still fits into an existing framework. In addition, some may be skeptical that the microbiome could be influencing children’s behavior, but remember that the bacteria within us have been evolving along with us for so long that nothing should surprise us. The next time the parents out there are dealing with their unruly children, you can kill two birds with one stone by punishing them by making them eat sauerkraut or kimchi!