胆石症和大肠癌在西方国家常见,在亚非地区则少见。两者都与饮食、特别是“纤维缺乏”有关,且都与胆汁酸盐代谢异常有关。胆汁中胆固醇过饱和可形成胆固醇性结石,这是由于胆汁酸盐的异常分泌或合成所致。胆固醇在胆汁中的溶解度随鹅脱氧胆酸的比例增加而增加,而脱氧胆酸的比例增加时则其溶解度下降;此为鹅脱氧胆酸治疗胆石症的部分根据。高纤维饮食可减少胆汁中的脱氧胆酸,此或因其阻碍脱氧胆酸远端肠道的吸收或因减少肠道细菌产生(脱氧胆酸)之故。大肠内胆汁酸代谢产物增多认为参与大肠癌的形成,如果此说正确,则可预料在这类患者身上此两种疾病会伴随出现。但早期研究的结果并不令人鼓舞。Doouss和Castleden研究了尸检者和大肠癌患者的胆石症流行 Cholelithiasis and colorectal cancer are common in western countries and rare in Asia and Africa. Both are related to diet, especially “fiber deficiency,” and are associated with abnormal bile acid salt metabolism. Cholesterol supersaturation can form cholesterol stones, which is due to abnormal secretion or synthesis of bile salts. The solubility of cholesterol in bile increases with increasing proportion of chenodeoxycholic acid, whereas the solubility decreases with increasing proportion of deoxycholic acid; this is in part based on chenodeoxycholic acid treatment of cholelithiasis. High-fiber diet can reduce the bile deoxycholic acid, either because it hinders the absorption of distal deoxycholic acid intestinal or reduce intestinal bacteria (deoxycholic acid) of the reason. The increase in bile acid metabolites in the large intestine is thought to be involved in the formation of colorectal cancer, and if this is correct, it is expected that these two diseases will be present in these patients. However, the results of earlier studies are not encouraging. Doouss and Castleden examined the prevalence of cholelithiasis in autopsy and colorectal cancer patients