In a first-of-its-kind study, researchers have trekked to several remote Tibetan Buddhist temples to study the gut microbiomes of meditating monks. The findings suggest the long-term practice of deep meditation could positively impact gut bacteria composition.
For years researchers have been studying the impact of meditation on physical and mental health. The simple daily practice has been associated with a number of positive outcomes but exactly how meditation could be generating physiological improvements has been unclear.
A 2017 review of 18 meditation studies speculated the practice can alter the expression of certain genes influencing inflammation. While this was hypothesized as a possible mechanism underpinning some of the positive effects of meditation, the molecular processes at work were still a mystery.
Following recent studies uncovering the many ways our gut-brain axis can influence inflammation, metabolism and mood, the new research set out to explore the potential relationship between meditation and the gut microbiome. To do this, the researchers turned to isolated Tibetan Buddhist monks who spend many hours a day meditating.
Thirty-seven Buddhist monks from three remote temples in Tibet were recruited to supply fecal samples for microbiome analysis. Each participant meditated for an average of two hours each day, for up to 30 years.
To isolate any microbiome differences that could be directly related to meditation, the researchers collected microbiome samples from a control group consisting of residents neighboring the temples. The study noted significant challenges in recruiting an adequate control group due to the sparsity of subjects in the regions. After eliminating those taking antibiotics or probiotics, and matching their diet, age and health with the monks, the researchers found 19 neighboring residents for the control group.
"We found that several bacterial species differed significantly between the meditation and control groups," the researchers reported in the new study. "Bacteria enriched in the meditation group at the genus level had a positive effect on human physical and mental health. This altered intestinal microbiota composition could reduce the risk of anxiety and depression and improve immune function in the body."
Prevotella and Bacteroides bacterial species were most significantly enriched in the meditation group. These two species have been previously associated with positive mental health and low rates of depression and anxiety.
Although the findings are deeply fascinating the researchers do indicate they need to be interpreted with caution. The cohort of subjects is incredibly small, and while the researchers did try to match the control group as closely as possible to the monks the findings cannot directly conclude the microbiome differences detected are solely caused by meditation.
Arianna Basile, from the University of Cambridge, also stresses the findings cannot be used as evidence meditation improves mental health via the microbiome. Basile, who didn't work on the new study, said there may be some evidence meditation can help mild mental health disorders, these novel findings don't offer huge insights into the association.
“The researchers were able to look at the different functions of the fecal microbiota and, while they speculate on the impact of these functions, the study was not able to predict if they would actually change chemical processes in the body, and therefore the various health outcomes," noted Basile. “It’s also important to note that the sample size is small and while their 16S sequencing technique is fine, other techniques such as a metagenomic shotgun analysis would be able to analyze the gut microbiome at a species level which would have been much more informative.”
At the very least this new study is the first to try and investigate the long-term effects of meditation on the gut microbiome. It's also the first to do the incredibly hard practical work of tracking down remote Tibetan Buddhist monks and comparing their gut bacteria to local, non-meditating neighbors. The conclusions in the study certainly lean on lots of caveats, but it also offers intriguing new pathways for future researchers to follow.
"These results suggest that long-term deep meditation may have a beneficial effect on gut microbiota, enabling the body to maintain an optimal state of health," the researchers concluded. "This study provides new clues regarding the role of long-term deep meditation in regulating human intestinal flora, which may play a positive role in psychosomatic conditions and well-being."
The new study was published in the journal General Psychiatry.
