Social constructs and behaviors can predict microbiome composition

It has been well documented that the microbiome is linked to various health disorders or conditions such as obesity, cancer, heart disease, or autoimmune disease.  However, there are still many unknowns regarding specific host-species interactions and the exact role of the environment in shaping this relationship.  In particular, we do not entirely understand how social interactions can influence and even predict our microbiome compositions, nor do we truly understand the strength of this relationship.  Can our behaviors predict the composition of microbiota populations that reside inside of us?

A recent study addressed this by examining how social interactions can specifically influence and predict the gut microbiome compositions of baboons.  Baboons are highly social primates that live in extended family groups.  It has already been shown that common group membership and dietary intake can influence and predict gut microbiota composition.  However, there is a lack of understanding as to how more complex socially driven behaviors can modulate microbiota populations.  To address this, researchers examined grooming patterns in baboons – a characteristic primate behavior that solidifies social bonds – to assess whether these behaviors predicted microbiome populations.  Furthermore, researchers investigated if grooming patterns within groups could also predict microbiome composition, and if there are particular bacterial strains that have a greater aptitude toward social transmission.

Two distinct baboon groups of 48 animals in total that were geographically isolated by a few kilometers were studied in their respective natural habitats.  Behavioral observations and analyses were recorded and fecal samples were collected opportunistically to generate metagenomics data of the distal gut microbiota composition and genealogy.  In accordance with previous data, group membership was the strongest predictor of gut microbiome composition.  Additionally, group membership was shown to be the strongest predictor compared to other metrics including sex and age, explaining 18.6% of global variation in gut microbiota species.  Diet is a major confounding factor that the researcher’s considered, but they controlled for this variable by conducting the study in a homogenous savannah where food consumption was largely consistent between both groups. 

The researchers next turned to correlating grooming behaviors with variable microbiota gut composition, as it has been previously demonstrated that the “strength” of a grooming relationship can vary in baboons.  Data indicated that stronger grooming partners had higher degrees of similarities in respective gut microbiome composition; 51 out of 327 species were predicted by grooming strength.  Interestingly, the “socially enriched” bacterial species identified consisted of a cohort of gram negative bacteria that have been linked to health benefits in humans.

We have certainly grown to understand that the host-species relationship is variable and labile to external circumstance.  However, as this study indicates, the delicacy of this relationship may be extraordinarily profound – changing the dial on the strength our social interactions could shape the microbiome within us.  The correlation and predictive value of this relationship is an especially important consideration for human health.  If more confirmation of this relationship is demonstrated in the future, novel and creative behavioral preventive therapies can be devised to shape and/or manage our gut microbiome.  

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