In 2014, researchers comparing the National rugby team of Ireland and sedentary men reported in the journal Gut that being physically fit was associated with a greater diversity of gut bugs. But correlation vs causation was debated, as with many microbiome studies.
Newer research conducted in rodents has found that exercise, regardless of diet type, improved the makeup of the gut microbiome and raised the levels of butyrate, a short-chain fatty acid that nourishes the intestinal barrier and helps protect against colon cancer. Rob Knight, director of the Center for Microbiome Innovation at U.C. San Diego, told Vogue, “That people who move more have a more diverse microbiome is something that we noticed at my lab several years ago, but we couldn’t prove causality…these studies are incredibly exciting”
The newest research conducted by the same authors of the 2014 study showed that athletes had increases in beneficial fecal metabolites like short-chain fatty acids. “Our earlier work, also published in ‘Gut’, had shown that the microbiome of the athletes differed in composition from that of non-athletes, but now we have found that functional behaviour of the microbiome separates the athletes and controls to an even greater degree,” said Professor Fergus Shanahan, one of the study’s lead authors.