title: Effects of wheat bran and Olestra on objective measures of stool and subjective reports of GI symptoms.
abstract: OBJECTIVE
  The aim of this study was to compare the effects of two nondigested, nonabsorbed dietary components on objective and subjective measures of gastrointestinal (GI) function.
  
  
  METHODS
  A placebo-controlled parallel study compared the effects of wheat bran (20 g/day or 40 g/day in cereal), a well-known dietary fiber, with those of olestra (20 g or 40 g/day in potato chips), a nonabsorbed fat, on stool output, stool apparent viscosity (log peak force for extrusion [PF]), stool water content, and GI symptoms. Sixty subjects resided on a metabolic ward for 9 days: 3 days baseline and 6 days treatment.
  
  
  RESULTS
  Compared with placebo, consumption of 20 g/day wheat bran for 6 days resulted in a rapid (within 38 h) increase in mean (+/-SE) stool output (placebo, 150 +/- 29 g/day; bran, 246 +/- 35 g/day, p < 0.05), a directional increase in mean stool water content (placebo, 81.2 +/- 0.8%; bran, 83.9 +/- 0.8%), stool water output (placebo, 159 +/- 54 g/day; bran, 238 +/- 30 g/day), and bowel movement frequency (BM/day) (placebo, 2.2 +/- 0.4; bran, 2.6 +/- 0.4), and no stool-softening effect (placebo log PF, 2.9 +/- 0.1 g; bran log PF, 2.9 +/- 0.1 g). Wheat bran 40 g/day results were not significantly different from wheat bran 20 g/day. Compared with placebo, consumption of olestra 20 g/day and 40 g/day for 6 days showed no significant difference in mean stool output (151 +/- 18 g/day and 204 +/- 28 g/day, respectively), mean BM frequency (1.8 +/- 0.2 BM/day and 2.1 +/- 0.3 BM/day, respectively), and stool water output (138 +/- 13 g/day and 184 +/- 31 g/day, respectively), a significant (p < 0.05) decrease in stool water content (75.5 +/- 1.7% and 72.6 +/- 2.2%, respectively), and either no effect on stool apparent viscosity (olestra 20 g/day, mean log PF, 3.0 +/- 0.1 g) or a gradual stool-softening effect beginning study day 6 (olestra 40 g/day, log PF, 2.7 +/- 0.1 g). None of the treatment groups showed a significant increase in GI symptoms compared with placebo.
  
  
  CONCLUSIONS
  Consumption of wheat bran in excess of levels in a typical Western diet significantly increased stool output, but did not soften normal-viscosity stool nor result in an increase in common GI symptoms. The observed plateau effect for wheat bran at 40 g/day suggests a maximal mechanical stimulatory effect. Consumption of olestra in excess of usual snacking conditions did not result in a significant increase in stool output or common GI symptoms. At the highest level tested, olestra resulted in a gradual stool-softening effect after several days of consumption.
authors.affiliation: The Procter & Gamble Company, Cincinnati, Ohio, USA.
authors.forename: J
authors.initials: J
authors.lastname: McRorie
authors.forename: J
authors.initials: J
authors.lastname: Kesler
authors.forename: L
authors.initials: L
authors.lastname: Bishop
authors.forename: T
authors.initials: T
authors.lastname: Filloon
authors.forename: G
authors.initials: G
authors.lastname: Allgood
authors.forename: M
authors.initials: M
authors.lastname: Sutton
authors.forename: T
authors.initials: T
authors.lastname: Hunt
authors.forename: A
authors.initials: A
authors.lastname: Laurent
authors.forename: C
authors.initials: C
authors.lastname: Rudolph
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003672:Defecation; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D004043:Dietary Fiber / Q000494:pharmacology*; D004311:Double-Blind Method; D019358:Fat Substitutes / Q000494:pharmacology*; D005227:Fatty Acids / Q000494:pharmacology*; D005243:Feces; D005260:Female; D005414:Flatulence / Q000209:etiology; D006356:Heartburn / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D013395:Sucrose / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D004042:Dietary Fats, Unsaturated; D004043:Dietary Fiber; D019358:Fat Substitutes; D005227:Fatty Acids; D013395:Sucrose; C013692:sucrose polyester