Intestinal metabolism of a random-bonded polyglucose bulking agent in humans: in vitro and in vivo studies of hydrogen evolution.

In vivo and in vitro experiments were conducted to determine the extent of intestinal fermentation of polydextrose, a random-bonded glucose polymer proposed as a low-calorie bulking agent in weight-reducing diets. The evolution of hydrogen gas was the index of bacterial fermentation. Oral ingestion of 15 gm polydextrose by healthy volunteers produced a flat breath hydrogen response, equivalent to that of glucose, and significantly less than that of lactulose. In vitro incubation of a polydextrose solution with fecal homogenates produced 24.8% of the hydrogen production of a comparable glucose solution. When either milk or lactose-hydrolyzed milk containing 18 gm intrinsic carbohydrate was mixed with 18 gm polydextrose, a significantly greater breath hydrogen excretion was observed as compared with the respective beverages alone. There is minimal in vivo fermentation of polydextrose when consumed alone, but when mixed into foods it may produce carbohydrate malabsorption or itself be more readily fermented.