title: Prevention of colonic aberrant crypt foci and modulation of large bowel microbial activity by dietary coffee fiber, inulin and pectin.
abstract: The present experiments were aimed at developing novel dietary fibers to aid in reduction of colon cancer risk. We assessed the effects of coffee (non-fiber fraction), coffee fiber (arabino-galactose polymer) and inulin (oligo-fructose) in male F344 rats using formation of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in the colon as the measure of preventive efficacy (or lack of such). At 5 weeks of age, groups of rats were fed the AIN-76A (control) and experimental diets that contained 1% coffee, 10% coffee fiber, 10% inulin, 10% pectin (positive control for fiber) or 200 p.p.m. piroxicam (a known ACF inhibitor). At 7 weeks of age, all animals were s.c injected with AOM (15 mg/kg body wt) once weekly for 2 weeks. All rats were killed 8 weeks after the last AOM injection and ACF were counted. The contents of the cecum were analyzed for bacterial beta-glucuronidase activity and short-chain fatty acids (SCFAs). Dietary administration of coffee fiber significantly suppressed AOM-induction of colonic ACF, in terms of total number, as well as crypt multiplicity and number of ACF/cm2 colon (P < 0.01-0.001). Inulin diet had no significant effect on total ACF, but had reduced the number of ACF/cm2 (P < 0.05). Whereas coffee had no effect on ACF formation, 10% pectin diet and 200 p.p.m. piroxicam significantly suppressed colonic ACF (P < 0.001) as had been expected. A significant reduction of cecal beta-glucuronidase activity was observed in the rats fed coffee, coffee fiber and pectin diets. Further, coffee fiber, inulin and pectin increased cecal SCFA levels 3- to 5-fold. These results suggest that coffee fiber can prevent colon cancer risk. Further studies are warranted to determine the full potential of this fiber in pre-clinical efficacy studies.
authors.affiliation: Chemoprevention Program, American Health Foundation, Valhalla, NY 10595, USA.
authors.forename: C V
authors.initials: CV
authors.lastname: Rao
authors.forename: D
authors.initials: D
authors.lastname: Chou
authors.forename: B
authors.initials: B
authors.lastname: Simi
authors.forename: H
authors.initials: H
authors.lastname: Ku
authors.forename: B S
authors.initials: BS
authors.lastname: Reddy
mesh_terms: D000818:Animals; D001419:Bacteria / Q000201:enzymology; D001835:Body Weight; D003069:Coffee / Q000737:chemistry*; D003106:Colon / Q000382:microbiology / Q000473:pathology*; D004043:Dietary Fiber / Q000494:pharmacology*; D005966:Glucuronidase / Q000378:metabolism; D007444:Inulin / Q000494:pharmacology*; D008297:Male; D010368:Pectins / Q000494:pharmacology*; D011230:Precancerous Conditions / Q000517:prevention & control*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D003069:Coffee; D004043:Dietary Fiber; D010368:Pectins; D007444:Inulin; D005966:Glucuronidase