title: Resistant Starch Bagels Reduce Fasting and Postprandial Insulin in Adults at Risk of Type 2 Diabetes.
abstract: BACKGROUND
  Type 2 diabetes (T2D) incidence continues to rise. Although increasing dietary fiber intake is an established strategy for improved glycemic control, most adults consume insufficient amounts. Fiber-enhanced functional foods can increase fiber intake, and there is particular interest in resistant starch (RS) as a high-fiber ingredient. Studies show that high-amylose maize resistant starch, type 2 (HAM-RS2) improves acute and chronic glycemic responses, but more studies are needed in individuals at high risk of T2D with RS delivered in commonly consumed foods.
  
  
  OBJECTIVE
  The objective of this study was to examine the chronic effects of consuming bagels high in HAM-RS2 on fasting and postprandial glycemic markers in adults at increased risk of T2D.
  
  
  METHODS
  With the use of a randomized, double-blind crossover design, 24 men and women with a mean ± SE age of 55.3 ± 1.59 y and body mass index (in kg/m2) of 30.2 ± 0.57 consumed 1 bagel containing 25 g HAM-RS2/d or 1 control wheat bagel/d for 56 d each, separated by a 4-wk washout. Fasting and postprandial oral-glucose-tolerance test (OGTT) glucose and insulin were measured on study days 1 and 57 of each bagel treatment.
  
  
  RESULTS
  The RS bagel treatment resulted in significantly lower fasting (22.1%, P = 0.04), 2-h (23.3%, P < 0.008), and 3-h (18.9%, P = 0.05) insulin incremental areas under the curve and fasting insulin resistance (homeostasis model assessment of insulin resistance; 23.1%, P = 0.04) than did the control bagel treatment. Fasting and postprandial OGTT glucose concentrations did not differ between the RS and control bagel treatments on study days 1 or 57.
  
  
  CONCLUSIONS
  These data suggest that consumption of a high-HAM-RS2 bagel improves glycemic efficiency by reducing the amount of insulin required to manage postprandial glucose while improving fasting insulin sensitivity in adults at increased risk of T2D. This research provides support for a feasible dietary strategy for T2D risk reduction. This trial was registered at clinicaltrials.gov as NCT02129946.
authors.affiliation: Departments of Human Health and Nutritional Sciences and.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Dainty
authors.affiliation: Departments of Human Health and Nutritional Sciences and.
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Klingel
authors.affiliation: Departments of Human Health and Nutritional Sciences and.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Pilkey
authors.affiliation: Departments of Human Health and Nutritional Sciences and.
authors.forename: Evan
authors.initials: E
authors.lastname: McDonald
authors.affiliation: Canada Bread Company Limited, Toronto, Canada.
authors.forename: Bruce
authors.initials: B
authors.lastname: McKeown
authors.affiliation: Molecular and Cellular Biology, University of Guelph, Guelph, Canada; and.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Emes
authors.affiliation: Departments of Human Health and Nutritional Sciences and amduncan@uoguelph.ca.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Duncan
mesh_terms: D001786:Blood Glucose; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D005504:Food Analysis; D006801:Humans; D007328:Insulin / Q000097:blood*; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D013213:Starch
chemical_list: D001786:Blood Glucose; D007328:Insulin; D008055:Lipids; D013213:Starch
keywords: HAM-RS2; bagel; functional food; glucose; high-amylose maize; insulin; postprandial; resistant starch; type 2 diabetes