title: The effects of and interactions between fermentable dietary fiber and lipid in germfree and conventional mice.
abstract: OBJECTIVE
  Dietary fiber can stimulate intestinal epithelial cell proliferation. The aim of this study was to resolve the different roles of fermentation and intraluminal viscosity on this trophic action and to investigate reported interactions between fiber and dietary fat.
  
  
  METHODS
  Conventional and germfree mice were fed guar gum in combination with low- or high-lipid diets for 2 weeks, and crypt cell production rates were determined.
  
  
  RESULTS
  Guar gum significantly stimulated proliferation in the small intestine, especially when combined with fat. Lipid itself also stimulated proliferation in the small intestine and had a direct trophic effect in the cecum and colon of the germfree mice. Fiber markedly stimulated proliferation in the cecum and colon but only in the conventional group. Interactions between lipid and bacteria and between guar gum and bacteria were also observed in the small intestine.
  
  
  CONCLUSIONS
  Guar gum has a trophic effect in the small bowel, probably related to viscosity, in addition to its fermentation-related actions in the colon. Positive interaction with lipid may be associated with delayed absorption. Lipid also has its own direct actions on small bowel mucosal proliferation, which are attenuated by the presence of bacteria.
authors.affiliation: Institute of Food Research, Norwich Laboratory, England.
authors.forename: J D
authors.initials: JD
authors.lastname: Pell
authors.forename: I T
authors.initials: IT
authors.lastname: Johnson
authors.forename: R A
authors.initials: RA
authors.lastname: Goodlad
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D004041:Dietary Fats / Q000494:pharmacology*; D004043:Dietary Fiber; D005285:Fermentation; D005685:Galactans / Q000494:pharmacology*; D005856:Germ-Free Life; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000166:cytology*; D008297:Male; D008351:Mannans / Q000494:pharmacology*; D051379:Mice; D053149:Plant Gums; D014783:Viscosity
chemical_list: D004041:Dietary Fats; D004043:Dietary Fiber; D005685:Galactans; D008351:Mannans; D053149:Plant Gums; C007894:guar gum