Social stress leads to changes in gut bacteria

Exposure to psychological stress in the form of social conflict alters gut bacteria in Syrian hamsters, according to a new study by Georgia State University.

It has long been said that humans have "gut feelings" about things, but how the gut might communicate those "feelings" to the brain was not known. It has been shown that gut microbiota, the complex community of microorganisms that live in the digestive tracts of humans and other animals, can send signals to the brain and vice versa.

In addition, recent data have indicated that stress can alter the gut microbiota. The most common stress experienced by humans and other animals is social stress, and this stress can trigger or worsen mental illness in humans. Researchers at Georgia State have examined whether mild social stress alters the gut microbiota in Syrian hamsters, and if so, whether this response is different in animals that "win" compared to those that "lose" in conflict situations.

Hamsters are ideal to study social stress because they rapidly form dominance hierarchies when paired with other animals. In this study, pairs of adult males were placed together and they quickly began to compete, resulting in dominant (winner) and subordinate (loser) animals that maintained this status throughout the experiment. Their gut microbes were sampled before and after the first encounter as well as after nine interactions. Sampling was also done in a control group of hamsters that were never paired and thus had no social stress.

Posted by Dr. Tim Sandle