Insulin-sensitizing effects on muscle and adipose tissue after dietary fiber intake in men and women with metabolic syndrome

J Clin Endocrinol Metab. 2012 Sep;97(9):3326-32. doi: 10.1210/jc.2012-1513. Epub 2012 Jun 28.

Abstract

Context: Dietary fibers have been associated with a reduced incidence of type 2 diabetes mellitus in epidemiological studies; however, the precise mechanisms are unknown.

Objective: The objective of the study was to evaluate the efficacy and site of action of an insoluble dietary fiber derived from maize (HAM-RS2) in improving insulin resistance in subjects at increased risk of type 2 diabetes mellitus.

Design: This study was a randomized, controlled crossover, dietary intervention study.

Setting: The study was conducted at the Centre for Diabetes, Endocrinology, and Research, Royal Surrey County Hospital, Guildford, United Kingdom.

Participants: Fifteen men and women with insulin resistance participated in the study.

Intervention: The intervention included 40 g/d HAM-RS2 compared with a matched placebo for 8 wk.

Main outcome measures: After each supplement, participants underwent a two-step hyperinsulinemic-euglycemic clamp study with the addition of glucose tracers; a meal tolerance test; arteriovenous sampling across forearm muscle tissue; and a sc adipose tissue biopsy for assessment of gene expression.

Results: There was enhanced uptake of glucose into the forearm muscle measured by arteriovenous sampling (65 ± 15% increase after resistant starch; P < 0.001). Adipose tissue function was also affected, with enhanced fatty acid suppression after HAM-RS2 treatment and an increase in gene expression for hormone sensitive lipase (P = 0.005), perilipin (P = 0.011), lipoprotein lipase (P = 0.014), and adipose triglyceride lipase (P = 0.03) in biopsy samples. There was no effect on the insulin sensitivity of hepatic glucose production or plasma lipids after HAM-RS2.

Conclusion: HAM-RS2 improved peripheral but not hepatic insulin resistance and requires further study as an intervention in patients with or at risk for type 2 diabetes.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / drug effects*
  • Adipose Tissue / metabolism*
  • Adult
  • Aged
  • Biomarkers / analysis
  • Biomarkers / metabolism
  • Biopsy
  • Cytokines / metabolism
  • Diet
  • Dietary Fiber / pharmacology*
  • Female
  • Gene Expression / drug effects
  • Glucose / metabolism
  • Glucose Clamp Technique
  • Humans
  • Insulin Resistance / physiology*
  • Lipid Metabolism / drug effects
  • Liver / metabolism
  • Male
  • Membrane Potentials / drug effects
  • Metabolic Syndrome / diet therapy*
  • Metabolic Syndrome / metabolism*
  • Metabolic Syndrome / physiopathology
  • Middle Aged
  • Muscles / drug effects*
  • Muscles / metabolism*
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Single-Blind Method
  • Zea mays / chemistry

Substances

  • Biomarkers
  • Cytokines
  • Dietary Fiber
  • RNA, Messenger
  • Glucose

Associated data

  • ISRCTN/ISRCTN56997186