A recent paper published in the journal Trends in Neuroscience calls attention to the new concept of “psychobiotics”, in which changes in gut microbes have an effect on mental health.
One author of the study, Dr. Philip Burnet, an associate professor of psychiatry at the University of Oxford explained, saying “We have suggested that any intervention that has a psychological effect through changes in the gut microbiome, is potentially a psychobiotic. This may include diet and exercise, both of which affect the bacterial communities in the gut, and both influence mood and cognition.
Gut microbes can significantly affect mood and cognition. Scientists are now trying to determine how this gut-brain connection could best be used to treat psychiatric illness.
Preliminary research has shown that raising the levels of “good” bacteria in the gut lower inflammation and cortisol levels, reduce stress reactivity, control depression and anxiety, improve memory, and reduce social anxiety. Most of these studies were, however, conducted on mice, so further research on human will be necessary for more concrete results.
“Those studies give us confidence that gut bacteria are playing a causal role in very important biological processes, which we can then hope to exploit with psychobiotics,” said Burnet.
Fermented foods like yogurt or sauerkraut offer psychobiotic benefits, along with exercise and staying away from saturated fats. This may explain some of the already established psychological benefits of such practices. Of course, the concept of psychobiotics also includes anything that can have a negative effect on the gut microbiome, such as some antibiotics, anti-depressants, and anti-psychotics.
According to Burnet:
“We wanted to increase awareness of the potential involvement of gut bacteria in the modulation of brain function, because the growth and perpetuation of microbial communities in our gut are influenced by so many factors in our lives. The concept of a psychobiotic will encourage us to make life choices that could ultimately reduce the incidence of mental disorders, and/or help boost the efficacy of current medication.”
Burnet also raises the question of whether they will need to become more regulated as we learn how they affect the central nervous system.
Signals cross the blood-brain barrier through the enteric nervous system, a part of the nervous system that governs the gastrointestinal system, as well as the vagus nerve, which connects the brain and the gut. The immune system, and hormones within the gut can also serve as a pathway for this communication.