Shanghai Mental Health Center Jiao Tong University School of Medicine recently set out to investigate whether there is evidence to support improvement of anxiety symptoms by regulating intestinal microbiota.

The Study

Increasing research has evidenced that gut microbiota can help regulate the brain function through something called “gut-brain axis.” Gut Microbiota are the trillions of microorganisms in the gut which perform important functions in the immune system and metabolism by providing essential inflammatory mediators, nutrients and vitamins.

Additionally, recent research suggests that mental disorders can be treated by regulating the intestinal microbiota, but there is no direct evidence to support this, reports Science Daily.

Hence, a team from Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, designed a study to investigate if there was evidence to support improvement of anxiety symptoms by regulating intestinal microbiota. The team reviewed 21 studies that had assessed 1,503 patients.


The researchers found that probiotic supplements in seven studies within their analysis contained only one kind of probiotic, two studies used a product that contained two kinds of probiotics, and the supplements used in the other five studies included at least three kinds.

Overall, 11 of the 21 studies showed a positive effect on anxiety symptoms by regulating intestinal microbiota, meaning that more than half (52%) of the studies showed this approach to be effective, although some studies that had used this approach did not find it worked.

Of the 14 studies that had used probiotics as the intervention, more than a third (36%) found them to be effective in reducing anxiety symptoms, while six of the remaining seven studies that had used non-probiotics as interventions found those to be effective—a 86% rate of effectiveness.

Some studies had used both the IRIF (interventions to regulate intestinal microbiota) approach and treatment as usual.

In the five studies that used treatment as usual and IRIF as interventions, only studies that had conducted non-probiotic ways got positive results, that showed a reduction in anxiety symptoms.


Researchers noted, “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. More studies are needed to clarify this conclusion since we still cannot run meta-analysis so far.”

Source: ScienceDaily

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