Can Gut Bacteria Explain Your Mood?

Is it possible that gut bacteria can alter your mood? A New York Times Magazine Article released in June poses the question – and the answer – which scientists believe is yes. Recent studies show that when “healthy” gut bacteria, like lactobacilli, are transferred to highly stressed animals, stress levels are reduced. Norwegian scientists found that some strains of gut bacteria are more common in those suffering from depression, and recent studies have shown that antibiotic use (which destroys gut bacteria and can cause an overpopulation of pathogenic bacteria) can be linked to more reckless behavior in mice. Germ-free mice raised without microbes demonstrate more anxious behavior, validating the notion that microbes are important for our physical as well as mental health.

But how do the bacteria residing in our digestive tract affect the traits that are regulated by our central nervous system? The chemicals used by our neurons to communicate and regulate mood, namely dopamine, serotonin, and gamma-aminobutyric acid (GABA), are all secreted by gut bacteria. They enter the blood stream and seep though the blood brain barrier, ultimately altering the brain and in turn, mood and behavior.

The specific mechanisms that allow the gut to communicate with the brain are still a bit murky, but what is clear is that the two share a close link and that the type of bacteria that inhabit your gut has “enormous implications for the sense of self,” according to Tom Insel, the director of the National Institute of Mental Health. “We are more microbial, at least from the standpoint of DNA, than human”

Research showing a link between gut bacteria, mood, and behavior is still in its infancy, but preliminary studies indicate that bacteria may be a viable treatment for many neurological-related disorders, and scientists are hopeful that ‘psychobiotics’ will be used in the future to treat anxiety, depression, autism, hyperactivity, and more.

By: Dr. Robynne Chutkan