title: Combining wheat bran with resistant starch has more beneficial effects on fecal indexes than does wheat bran alone.
abstract: BACKGROUND
  Wheat bran (WB) increases fecal bulk and hastens colonic transit, whereas resistant starch (RS) has effects on colonic fermentation, including increasing concentrations of butyrate.
  
  
  OBJECTIVE
  We hypothesized that a diet combining WB with RS would produce more favorable changes in fecal variables (eg, fecal bulk, rapid transit time, lower pH, and higher butyrate) than would WB alone.
  
  
  METHODS
  This was a randomized crossover block-design study for which 20 volunteers with a family history of colorectal cancer were recruited. The study included 3 diets: control, WB (12 g fiber/d), and WBRS (12 g WB fiber/d plus 22 g RS/d), each continued for 3 wk. In each diet, the major source of protein was lean red meat. During 5 consecutive days (days 15-19) of each dietary period, the subjects collected their total fecal output for analysis.
  
  
  RESULTS
  The WB diet resulted in greater fecal output (by 23% and 21% for wet and dry weights, respectively) and a lesser transit time (-11 h) than did the control diet but did not have major effects on fermentation variables. Compared with the control diet, the WBRS diet resulted in greater fecal output (by 56%) and a shorter transit time (-10 h), lower fecal pH (-0.15 units), higher fecal concentration (by 14%) and daily excretion (by 101%) of acetate, higher fecal concentration (by 79%) and daily excretion (by 162%) of butyrate, a higher fecal ratio of butyrate to total short-chain fatty acids (by 45%), and lower concentrations of total phenols (-34%) and ammonia (-27%).
  
  
  CONCLUSIONS
  Combining WB with RS had more benefits than did WB alone. This finding may have important implications for the dietary modulation of luminal contents, especially in the distal colon (the most common site of tumor formation).
authors.affiliation: Department of Gastroenterology, Monash University, Box Hill Hospital, Victoria, Australia. jane.muir@med.monash.edu.au
authors.forename: Jane G
authors.initials: JG
authors.lastname: Muir
authors.forename: Elaine G W
authors.initials: EG
authors.lastname: Yeow
authors.forename: Jennifer
authors.initials: J
authors.lastname: Keogh
authors.forename: Catherine
authors.initials: C
authors.lastname: Pizzey
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Bird
authors.forename: Ken
authors.initials: K
authors.lastname: Sharpe
authors.forename: Kerin
authors.initials: K
authors.lastname: O'Dea
authors.forename: Finlay A
authors.initials: FA
authors.lastname: Macrae
mesh_terms: D000328:Adult; D000368:Aged; D002087:Butyrates / Q000378:metabolism*; D003106:Colon / Q000187:drug effects* / Q000378:metabolism; D004032:Diet; D004043:Dietary Fiber / Q000008:administration & dosage / Q000627:therapeutic use*; D002149:Energy Intake; D005243:Feces / Q000737:chemistry; D005260:Female; D005285:Fermentation; D005772:Gastrointestinal Transit / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D013213:Starch / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D002087:Butyrates; D004043:Dietary Fiber; D013213:Starch