One of the most impactful health discoveries of the past couple of decades is the importance of our gut bacteria. Those little microbes hanging out in our intestines affect nearly every function of our bodies. Unfortunately, those little guys can also be rather easily affected 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 may be indirectly influencing the bacteria living in your gut.Right off the bat, we have to clarify that this is all based on a study of birds, specifically Seychelles warblers living on a small, isolated island. Mice are usually a pretty decent analog for human physiology, so the comparison to birds may not be as close. Still, the study’s findings are fascinating and may overlap with human social interaction.The People You Live With Could Be Affecting Your Gut Bacteria, Study FindsBirds that nested together, which were usually breeding pairs and helpers that incubate eggs and feed chicks, had more similar gut bacteria than those that lived in the same general territory but still maintained distance.The difference was especially noticeable in a specific class of microbes called anaerobic bacteria, which can’t survive in oxygen-rich environments and are usually passed through direct physical contact. This bacterium is strongly linked to social closeness: birds that interacted frequently shared it, whereas birds that didn’t interact shared it weren’t around each other very much.To find this out, researchers track hundreds of birds over multiple breeding seasons, while collecting and analyzing fecal samples to map their microbiomes. Since this population has been closely monitored for decades, scientists were able to separate social behavior from relatedness among the birds. The result is one of the clearest demonstrations yet that direct social interactions are the driving force behind this exchange of microbes. Simply existing within the same environment isn’t enough.To put this in human terms: you are constantly exchanging gut microbes with your roommates, and maybe not nearly as much with people living in other apartments in your building.While the results can’t be neatly mapped directly onto humans, studies have shown that human spouses and long-term cohabitants tend to develop similar gut microbiomes over time. Whether that’s helping or hurting us is another matter altogether.The post The People You Live With Have a Strange Effect on Your Body appeared first on VICE.