Effect of starch malabsorption on colonic function and metabolism in humans.

To study the impact of starch on colonic function and metabolism, 12 healthy volunteers consumed a controlled diet rich in starch for two 4-wk periods. In one of the study periods they received the glucosidase inhibitor acarbose (BAY g 5421) and placebo in the other. Stool wet weight increased by 68%, stool dry weight by 57%, fecal water content by 73%, and the mean transit time by 30% on acarbose. Breath hydrogen was significantly higher on acarbose, indicating stimulated carbohydrate fermentation in the colon. Fecal bacterial mass (+78%), total stool nitrogen (+53%), bacterial nitrogen (+200%), and stool fat (+56%) were higher in the acarbose than in the control period. The stimulation of fermentation in the human large intestine may be important in colonic and possibly other diseases.