The trillions of microorganisms that thrive in our gastrointestinal tract are essential to our health and immune system. Our bodies are teeming with bacteria, and a healthy gut needs these good microorganisms to help fend off harmful bacteria, break down food, and produce vitamins.
There has been a growing interest in the role gut flora play in mental health with studies suggesting depression and gut health are linked through the “gut-brain axis.”
Some research has suggested that regulating gut bacteria could help improve mental disorders like anxiety, one of the most common mental illnesses in the US, but so far there has been little conclusive evidence to back these claims.
In all, the 21 studies followed 1,5013 participants and 14 of the studies involved using probiotics while the other seven examined non-probiotic treatments like changing diet.
Some of the studies using probiotics tried two or three kinds of probiotics while some only used one probiotic.
Eleven out of 21 studies had positive results showing that regulating gut flora helped reduce anxiety symptoms.
The researchers found that the 14 studies that tested probiotics were 36 percent effective in total at reducing anxiety, but 6 out of 7 of the non-probiotic studies were effective in reducing anxiety.
In all the studies reviewed, there was an overall trend of the non-probiotic dietary changes being more effective than probiotics, especially when participants in a study tried both simultaneously.
According to the researchers, this is because changing a diet has a much more dramatic impact on improving and regulating the gut microbiota.
The results suggest that there is an essential connection between gut health and mental health, but more research is needed to understand this link.
Regulating gut bacteria could help reduce anxiety, but the researchers note that the study is observational with many limitations.
The researchers detailed their findings in a study published in the journal General Psychiatry.
“There are two kinds of interventions (probiotic and non-probiotic interventions) to regulate intestinal microbiota, and it should be highlighted that the non-probiotic interventions were more effective than the probiotic interventions,” the researchers said. “More studies are needed to clarify this conclusion since we still cannot run meta-analysis so far.”