We now know that our brains and guts influence each other — although many of the ways in which they are interlinked remain mysterious. A new study explores how stress related to conflict impacts gut bacteria, asking: is there a difference between how "winners" vs. "losers" are affected?

Research has shown that exposure to stress can affect our bodies in myriad ways, and that this can impact everything from the health of our hearts to that of our guts.

In fact, studies have even discovered that mood disorders are often linked with gastrointestinal discomfort, among other physical symptoms.

But several aspects of the brain-gut relationship remain unclear. For instance, if the stress we are exposed to comes from social conflict, does our final position — as "winners" or "losers" — as we emerge from that situation determine to what degree our microbiome is affected?

Scientists from Georgia State University in Atlanta set out to investigate this problem by looking at physiological changes occurring in Syrian hamsters when they had to deal with stressful situations.

These animals — apart from being a source of joy as adorable pets — lend themselves very well to research about biological responses to social stress. This is because, when placed together, they compete to establish hierarchies, splitting into dominant ("winning") and subordinate ("losing") animals.

Dr. Kim Huhman and colleagues worked with adult male hamsters and looked at how such stressful social situations would alter their gut microbiota. They predicted that hamster "losers" might be the most affected by conflict with the other animals — but their study revealed some surprises.

The results of this project were published in the journal Behavioural Brain Research.