title: Neutral detergent fiber, hemicellulose and cellulose digestibility in human subjects.
abstract: The fate of dietary fiber and its components was examined in seven women consuming low cellulose (LC) and high cellulose (HC) diets, each for about 1 month. The diets were of constant daily composition and differed only in that the HC diet contained an additional 16 g/day non-nutritive fiber (Solka Floc), which increased the neutral detergent fiber (NDF) of the diet from 9.5 to 23.5 g/day and Crampton and Maynard cellulose from 5.4 to 19.3 g/day. When apparent fiber digestibilities during 5-day periods were determined, both NDF and cellulose digestibilities varied greatly and inconsistently in each subject throughout both diet periods. Therefore, samples were pooled to form a single 20-30 day composite for each subject during each diet. Mean apparent NDF digestibility, after correcting for protein contamination in fecal NDF, was 70.4 +/- 7.3% during the LC diet and decreased to 23.0 +/- 15.0% during the HC diet. Cellulose digestibility was 69.7 +/- 10.7% without and 15.7 +2- 17.4% with the added cellulose. Hemicellulose was calculated as NDF minus cellulose. When the fecal NDF was corrected for protein contamination, hemicellulose digestibility averaged 71.7 +/- 5.4% during the LC diet and 51.0 +/- 7.9% during the HC diet. In a separate experiment, 16 g/day Solka Floc was ingested with a semi-purified liquid diet and only 8% of the cellulose was digested. These results suggest that more than half of the fiber in a LC diet containing fruits, vegetables and refined grains is degraded, while the apparent digestibility of refined cellulose is minimal.
mesh_terms: D000328:Adult; D002482:Cellulose / Q000378:metabolism*; D003902:Detergents; D004043:Dietary Fiber / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism*; D004063:Digestion; D005243:Feces / Q000032:analysis; D005260:Female; D005504:Food Analysis; D005526:Food, Formulated; D005769:Gastrointestinal Motility / Q000187:drug effects; D006801:Humans; D011134:Polysaccharides / Q000378:metabolism; D012995:Solubility
chemical_list: D003902:Detergents; D004043:Dietary Fiber; D011134:Polysaccharides; C007916:hemicellulose; D002482:Cellulose