title: Baseline insulin sensitivity affects response to high-amylose maize resistant starch in women: a randomized, controlled trial.
abstract: BACKGROUND
  Resistant starch (RS) is a type of dietary fiber that can improve glucose metabolism, but its effects may be modulated by sex or baseline insulin sensitivity. This study was designed to examine the effect of high-amylose maize resistant starch (HAM-RS2) on insulin sensitivity (SI) in women, and to determine if SI status affects the response to RS.
  
  
  METHODS
  This was a randomized, placebo-controlled, double-blind, cross-over study. Participants were 40 healthy, non-diabetic women aged 22-67 years in the normal-weight to obese BMI range (20.6-47.4 kg/m(2)). Two doses of HAM-RS2 were tested, 15 and 30 g per day, administered in the form of cookies. Participants were randomized to the order in which they received the experimental and placebo product. Each arm was 4 weeks, with a 4-week wash-out period in between. SI was assessed at the end of each 4-week arm of product consumption by frequently-sampled, insulin-modified, intravenous glucose tolerance test and minimal modeling. Participants were categorized as being insulin resistant (IR; SI < 7.8) or insulin sensitive (IS; SI ≥ 7.8) based on Gaussian analysis. The effect of treatment arm on SI was examined by mixed-model analysis within IR and IS sub-groups, using all available data. In addition, SI was examined by ANOVA among just those women who completed all three arms of the study with valid SI results.
  
  
  RESULTS
  Among IR participants, SI was on average ~16 % higher after the 30 g arm when compared to the control arm by mixed-model analysis (n = 40, P < 0.05), and tended to be 23 % higher by ANOVA among women who completed all arms (n = 23, P = 0.06). HAM-RS2 did not affect SI in IS women.
  
  
  CONCLUSIONS
  Consumption of HAM-RS2 at 30 g/day in the form of a snack food item was associated with improved insulin sensitivity in women with insulin resistance.
  
  
  BACKGROUND
  NCT0152806.
authors.affiliation: Department of Nutrition Sciences, University of Alabama at Birmingham (UAB), 616A Webb Building, 1675 University Blvd, Birmingham, AL 35294 USA.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Gower
authors.affiliation: Cedars-Sinai Diabetes and Obesity Research Institute, Los Angeles, CA USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Bergman
authors.affiliation: New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA.
authors.forename: Darko
authors.initials: D
authors.lastname: Stefanovski
authors.affiliation: Clinical Research Unit, UAB, Birmingham, USA.
authors.forename: Betty
authors.initials: B
authors.lastname: Darnell
authors.affiliation: Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, UAB, Birmingham, USA.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ovalle
authors.affiliation: Department of Human Studies, UAB, Birmingham, USA.
authors.forename: Gordon
authors.initials: G
authors.lastname: Fisher
authors.affiliation: Department of Nutrition Sciences, UAB, Birmingham, USA.
authors.forename: S Katherine
authors.initials: SK
authors.lastname: Sweatt
authors.affiliation: Department of Nutrition Sciences, UAB, Birmingham, USA.
authors.forename: Holly S
authors.initials: HS
authors.lastname: Resuehr
authors.affiliation: Ingredion, Incorporated, Bridgewater, NJ USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Pelkman
keywords: Intravenous glucose tolerance test; Minimal model