Probiotics for the brain? Study could pave the way for anti-stress injections

There’s a layer of living creatures covering each of our bodies, inside and out, from the tips of our fingers to the linings of our intestines. These microbes — many of them good, some of them bad, most of them benign — help us digest food, fend of disease, and contribute to our unique stench when we sweat.

Some promising studies have shown that certain microbes in the gut can have an effect on mental health, making people more or less anxious. So what if scientists could design an injection packed with beneficial microbes aimed at treating mental health disorders?

That’s the question that came to mind for Matt Frank, a psychology and neuroscience researcher at the University of Colorado, Boulder, after he and his colleagues injected rodents with probiotics in a recent study. In a paper published this week in the journal Brain, Behavior and Immunity, Frank and his team show that a particular bacterium can encourage a rodent’s brain into a state that resists inflammation, potentially paving the way for probiotic immunizations to treat stress-related mental disorders like PSTD and anxiety. More immediately, it might help treat inflammation-induced memory loss as a result of brain trauma.

“We have demonstrated for the first time that probiotic treatment induces an anti-inflammatory environment in the brain,” Frank told Digital Trends. “This effect of probiotic treatment was robust and long-lasting suggesting that this strain…of probiotic holds great promise to quell the neuro-inflammation associated with a number of disease conditions and disorders.”

The strain used by Frank and his team was Mycobacterium vaccae, an immune-improving microbe, which they injected into male rats. Rats that were injected on three occasions over the course of three weeks showed significantly higher levels of an anti-inflammatory protein in the area of the brain that moderates anxiety and fear.

“These findings suggest that some probiotics are capable of dampening inflammation in the brain,” Frank said. “Inflammation in the brain has profound negative effects on learning and memory as well as mood, thus some probiotics hold the promise of restoring immune balance in the brain and treating brain disorders involving inflammation.”

Frank noted that it’s not yet clear whether the benefits associated with Mycobacterium vaccae also exist for other probiotics, but said researchers are on the case. Frank and his team are now investigating how probiotic immunization encourages this anti-inflammatory brain environment in the hope of unlocking the secrets of how the immune system and brain communicate.