The metabolic consequences of slow colonic transit

Intestinal transit has a substantial influence on the enterohepatic circula tion of bile acids and steroid hormones, on colonic pH, and on short chain fatty acid concentrations in the distal colon. Slow transit is likely to fa vor disease processes that are related to over-efficient enterohepatic reci rculation and to lack of short chain fatty acid in the distal colon. These include gallstones, large bowel cancer, and possibly breast cancer. The bes t-documented influence of slow colonic transit is on bile acid metabolism. Slowing colonic transit increases deoxycholate and raises cholesterol satur ation of bile, making gallstone formation more likely. In this review, we a lso examine the evidence that slow colonic transit may be important in the etiology of large bowel and breast cancer. There is a lack of data pertaini ng to the relationship between colonic transit and diseases such as colon a nd breast cancer. Should slow colonic transit prove to be a significant fac tor in the etiology of such diseases, then the health of the population mig ht benefit from dietary and lifestyle changes that speed up intestinal tran sit. (Am J Gastroenterol 1999;94:2010-2016. (C) 1999 by Am. Coll. of Gastro enterology).