The people you live with have a strange effect on your body
One of the most impactful health discoveries of the last few decades is the importance of our gut bacteria. The tiny microbes that hang out in our intestines affect almost every function in our bodies. Unfortunately, the little guys can also be quite easily influenced by all sorts of external stimuli, from artificial sweeteners to medications, and even by the other people living in your home.
A study recently published in Molecular Ecology suggests that who you spend time with can indirectly affect the bacteria in your gut.
Right off the bat, we must clarify that all of this is based on a study of birds, specifically Seychelles warblers, that live on a small, isolated island. Mice are usually a pretty decent analog to human physiology, so the comparison to birds might not be that close. Still, the study’s findings are fascinating and may overlap with human social interaction.
The people you live with can influence your gut bacteria, study shows
Birds that nested together, which were usually breeding pairs and helpers incubating eggs and feeding young, had more similar gut bacteria than those that lived in the same general territory but still kept their distance.
The difference was particularly noticeable in a specific class of microbes called anaerobic bacteria, which cannot survive in oxygen-rich environments and usually pass through direct physical contact. This bacterium is strongly associated with social proximity: birds that interacted frequently shared it, while birds that did not interact shared it were not around each other much.
To find out, researchers are tracking hundreds of birds over multiple breeding seasons while collecting and analyzing fecal samples to map their microbiomes. As this population has been closely monitored for decades, scientists were able to separate social behavior from kinship among the birds. The result is one of the clearest demonstrations to date that direct social interactions are the driving force behind this exchange of microbes. It is not enough to simply exist in the same environment.
To put this in human terms: you’re constantly exchanging gut microbes with your roommates, and maybe not nearly as much with people who live in other apartments in your building.
Although the results don’t neatly map directly to humans, studies have shown that human spouses and long-term cohabitants tend to develop similar gut microbiomes over time. Whether it helps or hurts us is another matter entirely.
