Your gut bacteria deserves a raise: Those little guys are always working overtime, handling everything from helping you age better and keeping your immune system strong to fighting obesity. Now, a new study shows that popping probiotics (i.e., supplements of “good” bacteria) could also play a bigger role in your mental health than once thought—particularly when it comes to stress.
For a study published in the journal Brain, Behavior, and Immunity, researchers injected male rats with the immunoregulatory and anti-inflammatory (AKA very good for you) bacteria Mycobacterium vaccae once a week for three weeks to examine its effect on their brain, particularly regarding neuroimmune regulation, stress, and anxiety.
Eight days after the final injection, the rats had higher levels of the anti-inflammatory protein interleukin-4 in the hippocampus, a region of the brain that deals with cognitive function, anxiety, and fear. The idea that Mycobacterium vaccae may reduce brain inflammation is important because past studies have shown that brain inflammation increases the risk of mental disorders partly by affecting mood-influencing neurotransmitters like dopamine (AKA a happy chemical). Additionally, after subjecting the rats to a stressor, the researchers noted that the bacteria seemed to decrease the mental and physical effects of stress: The rodents had lower levels of stress-induced protein HMGB1, and they acted less anxious, too.
“We found that in rodents, this particular bacterium, Mycobacterium vaccae, actually shifts the environment in the brain toward an anti-inflammatory state. If you could do that in people, it could have broad implications for a number of neuroinflammatory diseases.” —lead study author Dr. Matthew Frank
Those results translate to great news for you: It could mean a probiotic immunization is on the way to fend off anxiety, depression, and even post-traumatic stress disorder (PTSD).
“We found that in rodents, this particular bacterium, Mycobacterium vaccae, actually shifts the environment in the brain toward an anti-inflammatory state,” lead study author Matthew Frank, PhD, says in a press release. “If you could do that in people, it could have broad implications for a number of neuroinflammatory diseases.”
Researchers say this particular strain of bacteria isn’t commercially available right now—so don’t waste any time hunting it down. Though that will hopefully change soon, other available probiotics may have a similar effect. “If you look at the field of probiotics generally, they have been shown to have strong effects in the domains of cognitive function, anxiety, and fear,” says senior author Christopher Lowry, PhD. “More research is necessary, but it’s possible that other strains of beneficial bacteria or probiotics may have a similar effect on the brain.”