Insulin-sensitizing effects of dietary resistant starch and effects on skeletal muscle and adipose tissue metabolism.

Journal article

BACKGROUND: Resistant starch may modulate insulin sensitivity, although the precise mechanism of this action is unknown. OBJECTIVE: We studied the effects of resistant starch on insulin sensitivity and tissue metabolism. DESIGN: We used a 4-wk supplementation period with 30 g resistant starch/d, compared with placebo, in 10 healthy subjects and assessed the results by using arteriovenous difference methods. RESULTS: When assessed by euglycemic-hyperinsulinemic clamp, insulin sensitivity was higher after resistant starch supplementation than after placebo treatment (9.7 and 8.5 x 10(-2) mg glucose x kg(-1) x min(-1) x (mU insulin/L)(-1), respectively; P = 0.03); insulin sensitivity during the meal tolerance test (MTT) was 33% higher (P = 0.05). Forearm muscle glucose clearance during the MTT was also higher after resistant starch supplementation (P = 0.03) despite lower insulin concentrations (P = 0.02); glucose clearance adjusted for insulin was 44% higher. Subcutaneous abdominal adipose tissue nonesterified fatty acid (NEFA; P = 0.02) and glycerol (P = 0.05) release were lower with resistant starch supplementation, although systemic NEFA concentrations were not significantly altered. Short-chain fatty acid concentrations (acetate and propionate) were higher during the MTT (P = 0.05 and 0.01, respectively), as was acetate uptake by adipose tissue (P = 0.03). Fasting plasma ghrelin concentrations were higher with resistant starch supplementation (2769 compared with 2062 pg/mL; P = 0.03), although postprandial suppression (40-44%) did not differ significantly. Measurements of gene expression in adipose tissue and muscle were uninformative, which suggests effects at a metabolic level. The resistant starch supplement was well tolerated. CONCLUSION: These results suggest that dietary supplementation with resistant starch has the potential to improve insulin sensitivity. Further studies in insulin-resistant persons are needed.

Authors: Robertson, MD; Bickerton, A; Dennis, A; Vidal, H; Frayn, K

• Publication status: Published
• Journal: American journal of clinical nutrition
• Volume: 82
• Issue: 3
• Pages: 559-567
• Publication date: 2005-09-01
• DOI: 10.1093/ajcn.82.3.559
• EISSN: 1938-3207
• ISSN: 0002-9165
• Language: English
• Keywords: Glucose Clamp Technique; Adult; Fatty Acids, Volatile; Starch; Postprandial Period; Insulin; Gene Expression; Fatty Acids, Nonesterified; Humans; Muscle, Skeletal; Blood Glucose; Adipose Tissue; Glucose Tolerance Test; Female; Male; Peptide Hormones; Ghrelin; Area Under Curve; Single-Blind Method; Cross-Over Studies; Dietary Carbohydrates; Middle Aged