title: Effect of resistant starch on colonic fermentation, bile acid metabolism, and mucosal proliferation.
abstract: Resistant starch is by definition that part of starch that escapes digestion in the small bowel. Cecal fermentation of resistant starch into short-chain fatty acids will result subsequently in a decrease in pH. Thus, resistant starch may have the same effect on colonic luminal contents and mucosa as some fiber components. We studied the effects of adding 45 g native amylomaize (Hylon-VII) to a standardized diet in 14 healthy volunteers on fermentation and colonic mucosal proliferation. Hylon-VII is a high amylose maize starch, containing 62% resistant starch. During amylomaize consumption, breath hydrogen excretion rose 85% and fecal short chain fatty acid output increased 35% (P < 0.01). Excretion of primary bile acids increased and the soluble deoxycholic acid concentration decreased by 50% (P = 0.002). Subsequently, cytotoxicity of the aqueous phase of feces--as measured on a colon cancer cell line--decreased (P = 0.007). Colonic mucosal proliferation in rectal biopsies (proliferating cell nuclear antigen immunostaining) decreased from 6.7 to 5.4% (P = 0.05). We speculate that resistant starch consumption decreases colonic mucosal proliferation as a result of the decreased formation of cytotoxic secondary bile acids, which is possibly mediated through acidification of the large bowel by production of short-chain fatty acids.
authors.affiliation: Department of Internal Medicine, Groot Ziekengasthuis, 's-Hertogenbosch, Nijmegen, The Netherlands.
authors.forename: I P
authors.initials: IP
authors.lastname: van Munster
authors.forename: A
authors.initials: A
authors.lastname: Tangerman
authors.forename: F M
authors.initials: FM
authors.lastname: Nagengast
mesh_terms: D000328:Adult; D000368:Aged; D001647:Bile Acids and Salts / Q000378:metabolism*; D002455:Cell Division; D003106:Colon / Q000378:metabolism* / Q000473:pathology; D003110:Colonic Neoplasms / Q000517:prevention & control; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D005260:Female; D005285:Fermentation / Q000502:physiology*; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012007:Rectum / Q000473:pathology; D013213:Starch / Q000494:pharmacology*
chemical_list: D001647:Bile Acids and Salts; D004040:Dietary Carbohydrates; D005232:Fatty Acids, Volatile; D013213:Starch