Could our personality be related to our microbiota?
Several studies carried out in humans described the influence of the intestinal microbiota on emotional behaviors through connexions between intestine and brain, although the underlying mechanisms are not yet fully understood. Could our microbiota shape our personality?
A Korean team tried to solve this mystery by studying the link between microbiota and personality based on the big five traits used by psychologists to describe a person: openness to experience, conscientiousness, extraversion, agreeableness (friendly/compassionate), neuroticism (emotional lability). After submitting 672 adults to a personality test, the researchers examined the composition of their intestinal microbiota, working on the assumption that the abundance or lack of certain bacteria could be related to specific personality traits.
According to the tests, a highly neurotic or conscientious personality seems to be directly associated to the microbiota composition. The tendency to neurosis could be correlated to the presence of bacterial groups known for their pro-inflammatory properties. As for the tendency to express dark thoughts, it seems to contribute to chronic inflammation over time. Less conscientious persons also seem to have a lower proportion of bacteria known for their anti-inflammatory properties. On the contrary, these bacteria appeared to be especially abundant in the most conscientious individuals.
Diversity and open-mindedness
Although significant differences were observed from one individual to another, the persons who are particularly open-minded or agreeable seem to have a more diverse microbiota. Why? The researchers are still cautious at this stage, but they believe this could be due to the ability of individuals having both personality traits to agree to try new foods or readily eat those that are offered to them (fruits and vegetables!). They consider that the results deserve to be confirmed and that the mechanisms involved have yet to be identified. But their work opens up new perspectives for the treatment of mental disorders: what if the best way to treat them was modulating the composition of the microbiota by eating healthier food?
Kim, H.-N., et al. Correlation between gut microbiota and personality in adults: A cross-sectional study. Brain Behav. Immun. (2017), https://doi.org/10.1016/j.bbi.2017.12.012