title: Efficacy of increased resistant starch consumption in human type 2 diabetes.
abstract: Resistant starch (RS) has been shown to beneficially affect insulin sensitivity in healthy individuals and those with metabolic syndrome, but its effects on human type 2 diabetes (T2DM) are unknown. This study aimed to determine the effects of increased RS consumption on insulin sensitivity and glucose control and changes in postprandial metabolites and body fat in T2DM. Seventeen individuals with well-controlled T2DM (HbA1c 46.6±2 mmol/mol) consumed, in a random order, either 40 g of type 2 RS (HAM-RS2) or a placebo, daily for 12 weeks with a 12-week washout period in between. AT THE END OF EACH INTERVENTION PERIOD, PARTICIPANTS ATTENDED FOR THREE METABOLIC INVESTIGATIONS: a two-step euglycemic-hyperinsulinemic clamp combined with an infusion of [6,6-(2)H2] glucose, a meal tolerance test (MTT) with arterio-venous sampling across the forearm, and whole-body imaging. HAM-RS2 resulted in significantly lower postprandial glucose concentrations (P=0.045) and a trend for greater glucose uptake across the forearm muscle (P=0.077); however, there was no effect of HAM-RS2 on hepatic or peripheral insulin sensitivity, or on HbA1c. Fasting non-esterified fatty acid (NEFA) concentrations were significantly lower (P=0.004) and NEFA suppression was greater during the clamp with HAM-RS2 (P=0.001). Fasting triglyceride (TG) concentrations and soleus intramuscular TG concentrations were significantly higher following the consumption of HAM-RS2 (P=0.039 and P=0.027 respectively). Although fasting GLP1 concentrations were significantly lower following HAM-RS2 consumption (P=0.049), postprandial GLP1 excursions during the MTT were significantly greater (P=0.009). HAM-RS2 did not improve tissue insulin sensitivity in well-controlled T2DM, but demonstrated beneficial effects on meal handling, possibly due to higher postprandial GLP1.
authors.affiliation: NutritionMetabolism and Diabetes Research Group, Faculty of Health and Medical Sciences, University of Surrey, Leggett Building, Guildford, Surrey GU2 7WG, UK Metabolic and Molecular Imaging GroupMRC Clinical Sciences Centre, Imperial College, London W12 0HS, UK Department of Food and Nutritional SciencesUniversity of Reading, Whiteknights Campus, Reading RG6 6AP, UK.
authors.forename: C L
authors.initials: CL
authors.lastname: Bodinham
authors.forename: L
authors.initials: L
authors.lastname: Smith
authors.forename: E L
authors.initials: EL
authors.lastname: Thomas
authors.forename: J D
authors.initials: JD
authors.lastname: Bell
authors.forename: J R
authors.initials: JR
authors.lastname: Swann
authors.forename: A
authors.initials: A
authors.lastname: Costabile
authors.forename: D
authors.initials: D
authors.lastname: Russell-Jones
authors.forename: A M
authors.initials: AM
authors.lastname: Umpleby
authors.forename: M D
authors.initials: MD
authors.lastname: Robertson
keywords: GLP1; euglycemic–hyperinsulinemic clamp; flux; stable isotopes