ACARBOSE ENHANCES HUMAN COLONIC BUTYRATE PRODUCTION

Earlier studies suggest that butyrate has colonic differentiating and nutritional effects and that acarbose increases butyrate production. T o determine the effects of acarbose on colonic fermentation, subjects were given 50-200 mg acarbose or placebo (cornstarch), three times per day, with meals in a double-blind crossover study. Fecal concentratio ns of starch and starch-fermenting bacteria were measured and fecal fe rmentation products determined after incubation of fecal suspensions w ith and without added substrate for 6 and 24 h. Substrate additions we re cornstarch, cornstarch plus acarbose and potato starch. Dietary sta rch consumption was similar during acarbose and placebo treatment peri ods, but fecal starch concentrations were found to be significantly gr eater with acarbose treatment. Ratios of starch-fermenting to total an aerobic bacteria were also significantly greater with acarbose treatme nt. Butyrate in feces, measured either as concentration or as percenta ge of total short-chain fatty acids, was significantly greater with ac arbose treatment than with placebo treatment. Butyrate ranged from 22. 3 to 27.5 mol/100 mol for the 50-200 mg, three times per day doses of acarbose compared with 18.3-19.3 mol/100 mol for the comparable placeb o periods. The propionate in fecal total short-chain fatty acids was s ignificantly less with acarbose treatment (10.7-12.1 mol/100 mol) than with placebo treatment (13.7-14.2 mol/100 mel). Butyrate production w as significantly greater in fermentations in samples collected during acarbose treatment, whereas production of acetate and propionate was s ignificantly less. Fermentation decreased when acarbose was added dire ctly to cornstarch fermentations. Acarbose effectively augmented colon ic butyrate production by several mechanisms; it reduced starch absorp tion, expanded concentrations of starch-fermenting and butyrate-produc ing bacteria and inhibited starch use by acetate- and propionate-produ cing bacteria.