The Anxiety and Depression Association of America estimates that 18% of adults in the United States suffer from an anxiety disorder. According to the World Health Organization, every 1 in 13 worldwide suffers from anxiety. Anxiety symptoms can also result from several other mental and physical illnesses. Therapies and medications are available, but what if there was another way to relieve those anxiety symptoms? Balancing gut bacteria may be a solution for anxiety sufferers.
Gut microbiota—the trillions of microorganisms which occur in the gut—provide essential inflammatory nutrients, mediators, and vitamins for the immune and metabolic systems. Some studies have indicated that the imbalance of intestinal gut microbiota is related to anxiety. Studies have shown that intestinal microbiota regulates brain function through the gut-brain axis, which includes the nervous, immune, and endocrine systems. However, until recently, there had been no consensus or evidence to support treating anxiety symptoms by regulating gut microbiota.
A team of researchers from the Shanghai Mental Health Center at the Shanghai Jiao Tong University School of Medicine aimed to determine whether anxiety symptoms should be treated by regulating intestinal microbiota. They performed a systematic review of randomized, controlled studies dating back to July 25, 2018. The review included 21 studies with a total of 1,503 participants. The results of their review were published last week in General Psychiatry.
Eleven of the 21 studies reviewed showed that regulating gut microbiota had positive effects on anxiety symptoms. Of the 21 studies, 14 of them—67%—recommended probiotics as an intervention to regulate intestinal microbiota. The remaining seven studies reviewed suggested non-probiotic dietary interventions, such as adjusting daily diet. The low FODMAP diet was used as a way to positively influence gut bacteria through dietary intervention. This diet aims to prevent digestive problems by cutting out foods which do not absorb in the small intestine, leaving a residue to ferment in the colon.
Although both ways of regulating gut microbiota are valid, the authors emphasized that the non-probiotic intervention was more effective than the probiotic intervention. The authors believe that the higher effectiveness of the non-probiotic intervention may be due to dietary changes, which might have more of an impact on gut bacteria growth than with probiotic supplements.
Because this was just an observational review of high-quality studies, the authors are careful not to establish causation. While they highly recommend further studies to clarify and support their conclusion, they also suggest considering regulating intestinal flora—in addition to the use of psychiatric drugs—as a way to alleviate anxiety symptoms.