Researchers have long known that the bacteria living in your gut can “talk” to your brain. Gut microbes, which collectively make up what’s called the gut microbiome, can have a significant impact on mood and cognition ― leading experts to deem the microbiome a new frontier in neuroscience.
Now, the challenge for scientists is to learn how to manipulate gut-brain communication to treat psychiatric illnesses.
Most previous studies on gut bacteria and mental health have focused on probiotics. Live, “good” bacteria that can be ingested in foods like yogurt or in supplement form, which have been shown to have anti-anxiety and anti-depressant effects.
But in a recent paper published in the journal Trends in Neuroscience, Oxford psychiatrists urge the scientific community to look beyond probiotics to consider a wider class of “psychobiotics” ― a new scientific term referring to any intervention that has an effect on mental health by way of changes in the gut microbiome.
“We have suggested that any intervention that has a psychological effect through changes in the gut microbiome, is potentially a psychobiotic,” Dr. Philip Burnet, an associate professor of psychiatry at the University of Oxford and one of the study’s authors, told The Huffington Post in an email. “This may include diet and exercise, both of which affect the bacterial communities in the gut, and both influence mood and cognition.”
So far, the research on psychobiotics is still preliminary. Studies have shown that increasing the amount of “good” bacteria in the gut can curb inflammation and cortisol levels, reduce symptoms of depression and anxiety, lower stress reactivity, improve memory, and even lessen neuroticism and social anxiety. However, most of these studies were conducted on mice, and more research on humans is needed.
“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,” Burnet said in a statement.
Why Treat The Brain With Psychobiotics
Luckily, some psychobiotics are behaviors you may already be engaged in, like exercising, eating gut-healthy foods like yogurt and sauerkraut, or maintaining a diet low in saturated fats. In fact, it’s possible the positive psychological effects of diet and exercise are partially mediated by the microbiome.
Anything that exerts a psychological effect, mediated by the microbiome, is potentially a psychobiotic, according to Burnet. This can include things that have a negative effect on gut flora, including some antibiotics, anti-depressants and anti-psychotics.
“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,” Burnet told HuffPost. “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.”
As the study’s authors argue, expanding the “psychobiotic” label should be prioritized as a way to exploit bacteria–brain communication for maximal benefit.
So how does this communication work? There are several main pathways by which signals from the gut travel through the body and cross the blood-brain barrier. Some of those core pathways include the enteric nervous system (a part of the nervous system located within and governing the function of the gastrointestinal system), the vagus nerve (connecting the brain and gut), the immune system and hormones within the gut.
Get Your Psychobiotics (Without A Prescription)
While you won’t find your doctor or therapist prescribing psychobiotics just yet, these sorts of treatments are already commercially available in the form of probiotic-rich foods like yogurt (which are often marketed as “bio-live” and “probiotic-rich”). Because they’re already a part of our diets, psychobiotics are somewhat like an unregulated form of mental health treatment, although we don’t tend to think of it that way.
“The larger question here, in medical, scientific, and legal terms, is that psychobiotics are not currently classified as a treatment,” Burnet said. “At most they are a dietary supplement. The answer to how and whether they should be regulated will emerge as we learn more about the effects of these substances on the central nervous system.”
Regulation would allow people to access psychobiotic treatments with proper guidelines for use and dosage, based on their particular needs.
A great deal more research on humans is needed before real treatments are made available. In the meantime, some medical experts are concerned about the widespread marketing of probiotics to consumers to treat psychiatric issues. Consumers should beware of the many probiotics marketed online as cognitive enhancers or mood boosters, according to Dr. Emeran Mayer, a gastroenterologist at the University of California, Los Angeles and author of The Mind-Gut Connection.
“I personally think that true psychobiotics which have undergone rigorous clinical testing and FDA approval will not be available before another five to 10 years from now,” Mayer said. However, he added, “the concept of developing psychobiotics in the future is exciting.”
While there’s a great deal of enthusiasm in the scientific world about the possibilities ― and rightfully so ― Burnet emphasized that psychobiotics should not been seen as a substitute for current psychotropic medications.
“The quality of life of many people suffering from mental illness has been improved by antidepressants, antipsychotics and so on, and so these drugs will always have a place in society,” he said. “However, there are also quite a few patients who do not respond to conventional medication, and this is where I think psychobiotics can come into play.
“These supplements should be used as ‘add-on’ or adjunctive therapies to improve the response of the brain to current medicines.”