Dietary fibers and absorption of nutrients.

Abstract

The increased intake of foods containing dietary fiber can generally be shown to result in increases in fecal volume and dry weight and in fecal energy content (1-3). These changes are in part directly attributable to increased consumption of undigestible plant cell wall material, but there is also evidence that the certain dietary fibers may also affect the digestion and absorption of other nutrients.The effect of dietary fiber on increased fecal energy content can be expressed by fruit, vegetable, or cereal fiber (4, 5) and has been reported to vary between 58 and 321 kcal/day, depending on the type and amount of dietary fiber ingested (4-7). This energy loss is largely in the form of fat and protein (7) and has been suggested to be of both bacterial and metabolic origin (8, 9).Generally, the effects of increasing intakes of fiber in the form of wheat bran have, at best, only a mild effect on fecal energy loss (10). A portion of this loss is due to fat which is closely associated with the bran and large...