Physical Activity as a Determinant of Fecal Bile Acid Levels

Abstract

Physical activity is protective against colon cancer, whereas colonic bile acid exposure is considered a risk factor. However, the relationship between physical activity and bile acid levels has not been well studied. A cross-sectional analysis of fecal bile acid levels was conducted for 735 colorectal adenoma formers of the ursodeoxycholic acid chemoprevention trial. Hours of recreational activity was found to be inversely related to total fecal bile acid concentrations among participants with low triglycerides, but not for those with high triglycerides. The distinct effects of physical activity between individuals with low versus high triglycerides are suggested to be related to changes in bile acid metabolism, as people with high triglycerides are more likely to have impaired bile acid absorption, thereby increasing bile acid excretion. These results suggest that the protective effect of physical activity may be mediated through decreased colonic bile acid exposure, but only in individuals with low triglycerides.