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

Am J Clin Nutr. 2005 Sep;82(3):559-67. doi: 10.1093/ajcn.82.3.559.

Abstract

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.

Publication types

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

MeSH terms

  • Adipose Tissue / metabolism*
  • Adult
  • Area Under Curve
  • Blood Glucose / metabolism
  • Cross-Over Studies
  • Dietary Carbohydrates / administration & dosage
  • Dietary Carbohydrates / pharmacology*
  • Fatty Acids, Nonesterified / analysis
  • Fatty Acids, Volatile / analysis
  • Female
  • Gene Expression
  • Ghrelin
  • Glucose Clamp Technique
  • Glucose Tolerance Test
  • Humans
  • Insulin / metabolism*
  • Male
  • Middle Aged
  • Muscle, Skeletal / metabolism*
  • Peptide Hormones / blood
  • Postprandial Period
  • Single-Blind Method
  • Starch / administration & dosage
  • Starch / pharmacology*

Substances

  • Blood Glucose
  • Dietary Carbohydrates
  • Fatty Acids, Nonesterified
  • Fatty Acids, Volatile
  • Ghrelin
  • Insulin
  • Peptide Hormones
  • Starch