title: The acute effects of inulin and resistant starch on postprandial serum short-chain fatty acids and second-meal glycemic response in lean and overweight humans.
abstract: Colonic fermentation of dietary fiber to short-chain fatty acids (SCFA) may protect against obesity and diabetes, but excess production of colonic SCFA has been implicated in the promotion of obesity. We aimed to compare the effects of two fermentable fibers on postprandial SCFA and second-meal glycemic response in healthy overweight or obese (OWO) vs lean (LN) participants.
  
  
  
  Using a randomized crossover design, 13 OWO and 12 LN overnight fasted participants were studied for 6 h on three separate days after consuming 300 ml water containing 75 g glucose (GLU) as control or with 24 g inulin (IN) or 28 g resistant starch (RS). A standard lunch was served 4 h after the test drink.
  
  
  
  Within the entire group, compared with control, IN significantly increased serum SCFA (P<0.001) but had no effect on free-fatty acids (FFA) or second-meal glucose and insulin responses. In contrast, RS had no significant effect on SCFA but reduced FFA rebound (P<0.001) and second-meal glucose (P=0.002) and insulin responses (P=0.024). OWO had similar postprandial serum SCFA and glucose concentrations but significantly greater insulin and FFA than LN. However, the effects of IN and RS on SCFA, glucose, insulin and FFA responses were similar in LN and OWO.
  
  
  
  RS has favorable second-meal effects, likely related to changes in FFA rather than SCFA concentrations. However, a longer study may be needed to demonstrate an effect of RS on SCFA. We found no evidence that acute increases in SCFA after IN reduce glycemic responses in humans, and we were unable to detect a significant difference in SCFA responses between OWO vs LN subjects.
authors.affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Rahat-Rozenbloom
authors.affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Fernandes
authors.affiliation: Biostatistics Unit, St. Joseph's Healthcare Hamilton, 50 Charlton East, Hamilton, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Department of Biochemistry, The University of Western Ontario, London, Ontario, Canada.
authors.forename: G B
authors.initials: GB
authors.lastname: Gloor
authors.affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.|Clinical Nutrition and Risk Factor Modification Centre, Division of Endocrinology and Metabolism, Li Ka Shing Knowledge Institute, St. Michael's Hospital Toronto, Toronto, Ontario, Canada.
authors.forename: T M S
authors.initials: TM
authors.lastname: Wolever
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000187:drug effects; D018592:Cross-Over Studies; D005232:Fatty Acids, Volatile / Q000097:blood*; D005260:Female; D006801:Humans; D056865:Ideal Body Weight / Q000502:physiology; D007328:Insulin / Q000097:blood; D007444:Inulin / Q000494:pharmacology*; D008297:Male; D062407:Meals / Q000187:drug effects; D008875:Middle Aged; D050177:Overweight / Q000097:blood / Q000188:drug therapy*; D019518:Postprandial Period / Q000187:drug effects*; D013213:Starch / Q000031:analogs & derivatives / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D005232:Fatty Acids, Volatile; D007328:Insulin; D013213:Starch; D007444:Inulin