Beijing: Regulating gut microorganisms by using probiotic and non-probiotic food and supplements may help people alleviate their anxiety levels, a review of studies suggests. Anxiety symptoms are common in people with mental diseases and a variety of physical disorders, especially those related to stress.

Research has indicated that gut microbiota — 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 — can help regulate brain function through something called the “gut-brain axis.”

Recent research also suggests that mental disorders could be treated by regulating the intestinal microbiota, but there is no specific evidence to support this. Researchers from Shanghai Jiao Tong University School of Medicine in China set out to investigate if there was evidence to support improvement of anxiety symptoms by regulating intestinal microbiota. They reviewed 21 studies that had looked at 1,503 people collectively.

Of the 21 studies, 14 had chosen probiotics as interventions to regulate intestinal microbiota (IRIFs), and seven chose non-probiotic ways, such as adjusting daily diets. Probiotics are living organisms found naturally in some foods that are also known as “good” or “friendly” bacteria because they fight against harmful bacteria and prevent them from settling in the gut.

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

Of the 14 studies that had used probiotics as the intervention, more than a third (36 per cent) 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 per cent rate of effectiveness. —PTI