Insulin-Sensitizing Effects on Muscle and Adipose Tissue after Dietary Fiber Intake in Men and Women with Metabolic Syndrome

• Published in: The journal of clinical endocrinology and metabolism Vol. 97; no. 9; pp. 3326 - 3332
• Main Authors: Robertson, M. Denise, Wright, John W., Loizon, Emmanuelle, Debard, Cyrille, Vidal, Hubert, Shojaee-Moradie, Fariba, Russell-Jones, David, Umpleby, A. Margot
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Oxford University Press 01.09.2012; Endocrine Society
• Subjects: Adipose tissue; Adipose Tissue - drug effects; Adipose Tissue - metabolism; Adult; Aged; Biological and medical sciences; Biomarkers - analysis; Biomarkers - metabolism; Biopsy; Body fat; Cytokines - metabolism; Diabetes; Diabetes mellitus (non-insulin dependent); Diet; Dietary fiber; Dietary Fiber - pharmacology; Dietary intake; Endocrinology; Endocrinopathies; Epidemiology; Feeding. Feeding behavior; Female; Forearm; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression - drug effects; Glucose; Glucose - metabolism; Glucose Clamp Technique; Glucose tolerance; Humans; Insulin resistance; Insulin Resistance - physiology; Lipase; Lipid Metabolism - drug effects; Lipids; Lipoprotein lipase; Liver; Liver - metabolism; Male; Medical sciences; Membrane Potentials - drug effects; Metabolic syndrome; Metabolic Syndrome - diet therapy; Metabolic Syndrome - metabolism; Metabolic Syndrome - physiopathology; Middle Aged; Muscles - drug effects; Muscles - metabolism; Real-Time Polymerase Chain Reaction; RNA, Messenger - biosynthesis; RNA, Messenger - genetics; Sampling; Single-Blind Method; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology; Zea mays - chemistry; Endocrinopathy; Human; Obesity; Pancreatic hormone; Adipose tissue; Nutrition; Nutrition disorder; Sex; Cardiovascular disease; Metabolic diseases; Male; Metabolic syndrome; Insulin; Female; Muscle; Woman; Dietary fiber; Endocrinology; Nutritional status
• ISSN: 0021-972X; 1945-7197; 1945-7197
• DOI: 10.1210/jc.2012-1513

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.