BACKGROUND:Diets high in cereal-fiber (HCF) have been shown to improve whole-body insulin sensitivity. In search for potential mechanisms we hypothesized that a supplemented HCF-diet influences the composition of the human gut microbiota and/or biomarkers of colonic carbohydrate fermentation. METHODS: We performed a randomized controlled 18-week intervention in group-matched overweight participants. Fecal samples of 69 participants receivingisoenergetic HCF (cereal-fiber 43 g/day), or control (cereal-fiber 14 g/day), or high-protein (HP, 28% of energy-intake, cereal-fiber 14 g/day), or moderately high cereal fiber/protein diets (MIX; protein 23% of energy-intake, cereal-fiber 26 g/day) with comparable fat contents were investigated for diet-induced changes of dominant groups of the gut microbiota, and of fecal short-chain fatty-acids (SCFA) including several of their proposed targets, after 0, 6, and 18-weeks of dietary intervention. In vitro fermentation of the cereal fiber extracts as used in the HCF and MIX diets was analyzed using gas chromatography. Diet-induced effects on whole-body insulin-sensitivity were measured using euglycaemic-hyperinsulinemic clamps and re-calculated in the here investigated subset of n = 69 participants that provided sufficient fecal samples on all study days. RESULTS:Gut microbiota groups and biomarkers of colonic fermentation were comparable between groups at baseline (week 0). No diet-induced differences were detected between groups during this isoenergetic intervention, neither in the full model nor in uncorrected subgroup-analyses. The cereal-fiber extract as used for preparation of the supplements in the HCF and MIX groups did not support in vitro fermentation. Fecal acetate, propionate, and butyrate concentrations remained unchanged, as well as potential targets of increased SCFA, whereas valerate increased after 6-weeks in the HP-group only (p = 0.037). Insulin-sensitivity significantly increased in the HCF-group from week-6 (baseline M-value 3.8 ± 0.4 vs 4.3 ± 0.4 mg·kg-1·min-1, p = 0.015; full model 0-18-weeks, treatment-x-time interaction, p = 0.046). CONCLUSIONS: Changes in the composition of the gut microbiota and/or markers of colonic carbohydrate fermentation did not contribute explaining the observed early onset and significant improvement of whole-body insulin sensitivity with the here investigated HCF-diet. TRIAL REGISTRATION: This trial was registered at http://www.clinicaltrials.gov as NCT00579657.
RCT Entities:
BACKGROUND: Diets high in cereal-fiber (HCF) have been shown to improve whole-body insulin sensitivity. In search for potential mechanisms we hypothesized that a supplemented HCF-diet influences the composition of the human gut microbiota and/or biomarkers of colonic carbohydrate fermentation. METHODS: We performed a randomized controlled 18-week intervention in group-matched overweight participants. Fecal samples of 69 participants receiving isoenergetic HCF (cereal-fiber 43 g/day), or control (cereal-fiber 14 g/day), or high-protein (HP, 28% of energy-intake, cereal-fiber 14 g/day), or moderately high cereal fiber/protein diets (MIX; protein 23% of energy-intake, cereal-fiber 26 g/day) with comparable fat contents were investigated for diet-induced changes of dominant groups of the gut microbiota, and of fecal short-chain fatty-acids (SCFA) including several of their proposed targets, after 0, 6, and 18-weeks of dietary intervention. In vitro fermentation of the cereal fiber extracts as used in the HCF and MIX diets was analyzed using gas chromatography. Diet-induced effects on whole-body insulin-sensitivity were measured using euglycaemic-hyperinsulinemic clamps and re-calculated in the here investigated subset of n = 69 participants that provided sufficient fecal samples on all study days. RESULTS: Gut microbiota groups and biomarkers of colonic fermentation were comparable between groups at baseline (week 0). No diet-induced differences were detected between groups during this isoenergetic intervention, neither in the full model nor in uncorrected subgroup-analyses. The cereal-fiber extract as used for preparation of the supplements in the HCF and MIX groups did not support in vitro fermentation. Fecal acetate, propionate, and butyrate concentrations remained unchanged, as well as potential targets of increased SCFA, whereas valerate increased after 6-weeks in the HP-group only (p = 0.037). Insulin-sensitivity significantly increased in the HCF-group from week-6 (baseline M-value 3.8 ± 0.4 vs 4.3 ± 0.4 mg·kg-1·min-1, p = 0.015; full model 0-18-weeks, treatment-x-time interaction, p = 0.046). CONCLUSIONS: Changes in the composition of the gut microbiota and/or markers of colonic carbohydrate fermentation did not contribute explaining the observed early onset and significant improvement of whole-body insulin sensitivity with the here investigated HCF-diet. TRIAL REGISTRATION: This trial was registered at http://www.clinicaltrials.gov as NCT00579657.
Authors: M O Weickert; M Mohlig; C Koebnick; J J Holst; P Namsolleck; M Ristow; M Osterhoff; H Rochlitz; N Rudovich; J Spranger; A F H Pfeiffer Journal: Diabetologia Date: 2005-09-20 Impact factor: 10.122
Authors: Martin O Weickert; Matthias Möhlig; Christof Schöfl; Ayman M Arafat; Bärbel Otto; Hannah Viehoff; Corinna Koebnick; Angela Kohl; Joachim Spranger; Andreas F H Pfeiffer Journal: Diabetes Care Date: 2006-04 Impact factor: 19.112
Authors: Sylvia H Duncan; Alvaro Belenguer; Grietje Holtrop; Alexandra M Johnstone; Harry J Flint; Gerald E Lobley Journal: Appl Environ Microbiol Date: 2006-12-22 Impact factor: 4.792
Authors: Matthias B Schulze; Mandy Schulz; Christin Heidemann; Anja Schienkiewitz; Kurt Hoffmann; Heiner Boeing Journal: Arch Intern Med Date: 2007-05-14
Authors: Marie-Christine Simon; Anna Lena Reinbeck; Corinna Wessel; Julia Heindirk; Tomas Jelenik; Kirti Kaul; Juan Arreguin-Cano; Alexander Strom; Michael Blaut; Fredrik Bäckhed; Volker Burkart; Michael Roden Journal: J Biol Chem Date: 2019-12-10 Impact factor: 5.157
Authors: John G Hattersley; Matthias Möhlig; Michael Roden; Ayman M Arafat; Christian V Loeffelholz; Peter Nowotny; Jürgen Machann; Johannes Hierholzer; Martin Osterhoff; Michael Khan; Andreas F H Pfeiffer; Martin O Weickert Journal: PLoS One Date: 2012-06-22 Impact factor: 3.240
Authors: Frederique Respondek; Philippe Gerard; Mathilde Bossis; Laura Boschat; Aurélia Bruneau; Sylvie Rabot; Anne Wagner; Jean-Charles Martin Journal: PLoS One Date: 2013-08-12 Impact factor: 3.240
Authors: Martin de Bock; José G B Derraik; Christine M Brennan; Janene B Biggs; Greg C Smith; David Cameron-Smith; Clare R Wall; Wayne S Cutfield Journal: PLoS One Date: 2012-07-27 Impact factor: 3.240