COLUMBUS, Ohio, March 21 (UPI) -- Stress can change the balance of bacteria that naturally live in the gut, which may explain why the stressed have less immunity, U.S. researchers say.
Lead researcher Michael Bailey of the Ohio State University said exposure to stress led to changes in composition, diversity and number of gut microorganisms. Bacterial communities in the intestine became less diverse and had greater numbers of potentially harmful bacteria, such as Clostridium -- a group of bacteria, some resistant to antibiotics.
"These changes can have profound implications for physiological function," Bailey said in a statement. "When we reduced the number of bacteria in the intestines using antibiotics, we found that some of the effects of stress on the immune system were prevented. This suggests that not only does stress change the bacteria levels in the gut, but that these alterations can, in turn, impact our immunity."
Gut bacteria stimulate the lymphoid tissue associated with the gut mucosa to produce antibodies to germs, which the immune system recognizes and fights harmful bacteria.
The findings are published in the journal Brain, Behavior and Immunity.