Large-Bowel Carcinogenesis: Fecal Constituents of Populations With Diverse Incidence Rates of Colon Cancer2

We studied the quantitative and qualitative aspects of fecal neutral sterols and bile acids and fecal β-glucuronidase activity from populations with various dietary patterns to elucidate the etiologic role of these compounds on colon cancer. The fecal microflora of Americans consuming a mixed Western diet were more able to hydrolyze glucuronide conjugates than were those of American vegetarians and Seventh-Day Adventists, and Japanese and Chinese. The daily fecal excretion of coprostanol, coprostanone, and total neutral sterols was higher in Americans than in other groups. Americans who ate a Westerntype diet excreted high levels of bile acids and more microbially degraded bile acids than did others. Our data showed a strong association between the incidence of colon cancer and the fecal bile acid and neutral sterol excretion.