title: Resistant starch intake at breakfast affects postprandial responses in type 2 diabetics and enhances the glucose-dependent insulinotropic polypeptide--insulin relationship following a second meal.
abstract: Resistant starch (RS) consumption can modulate postprandial metabolic responses, but its effects on carbohydrate (CHO) handling in type 2 diabetics (T2D) are unclear. It was hypothesized that a bagel high in RS would improve glucose and insulin homeostasis following the 1st meal, regardless of the amount of available CHO, and that in association with incretins, the effects would carry over to a 2nd meal. Using a randomized crossover design, 12 T2D ingested four different bagel treatments (their 1st meal) determined by available CHO and the weight or amount of bagel consumed: treatment A, without RS (50 g of available CHO); treatment B, with RS (same total CHO as in A); treatment C, with RS (same available CHO as in A); and treatment D, with the same RS as in B and available CHO as in A and C. A standard 2nd meal was ingested 3 h later. Following the first meal, B elicited a lower glucose incremental area under the curve (iAUC) than C (P < 0.05), D (P < 0.05), and A (trend; P = 0.07), lower insulin iAUC than A (P < 0.05) and C (P < 0.05), and lower glucose-dependent insulinotropic polypeptide (GIP) iAUC than A (P < 0.05). There was a positive correlation (P < 0.05) between GIP and insulin iAUCs after the 2nd meal, and C had a 3 times greater slope than the other treatments (r = 0.91, P < 0.001), yet lacked a significant concomitant improvement in glucose disposal. These results show that for the 1st meal, RS was effective when it replaced a portion of the available CHO, while ingesting more RS influenced the GIP-insulin axis following the 2nd meal.
authors.affiliation: Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.
authors.forename: Stacey
authors.initials: S
authors.lastname: MacNeil
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Rebry
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Tetlow
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Emes
authors.forename: Bruce
authors.initials: B
authors.lastname: McKeown
authors.forename: Terry E
authors.initials: TE
authors.lastname: Graham
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D062408:Breakfast; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D005947:Glucose; D006801:Humans; D007328:Insulin; D019518:Postprandial Period; D013213:Starch
chemical_list: D001786:Blood Glucose; D007328:Insulin; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D013213:Starch; D005947:Glucose