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ABSTRACT: Introduction
The effect of whole-grain (WG) versus refined-grain (RG) diets on glucose-stimulated insulin secretion (GSIS) and β-cell function is unclear.Methods
In a double-blind crossover randomized controlled trial, 13 prediabetic adults (37.2 ± 1.8 y, BMI: 33.6 ± 1.4 kg m-2 , 2 h glucose: 146.9 ± 11.6 mg dL-1 ) are provided isocaloric-matched WG and RG diets for 8-weeks each, with an 8-10 week washout between diets. Glucose, insulin, and C-peptide are studied over 240 min following a 75 g OGTT. Incretins (GLP-1 and GIP), PYY, and total ghrelin are assessed at 0, 30, and 60 min. Mixed-meal diets for carbohydrate (54%), fat (28%), and protein (18%) contain either WG (50 g/1000 kcal) or equivalent RG.Results
Both diets induce fat loss (≈2 kg). While neither diet impacts early phase GSIS, the WG diet increases total GSIS (iAUC of C-peptide0-240 /Glc0-240 , p = 0.02) and β-cell function (disposition index; GSIS × insulin sensitivity, p = 0.02). GIP and PYY are unaltered by either diet, but GLP-1 is higher at 30 min following RG versus WG (p = 0.04). Ghrelin levels are higher at 60 min of the OGTT following both interventions (p = 0.01).Conclusion
A WG-rich diet increases β-cell function independent of gut hormones in adults with prediabetes.
SUBMITTER: Malin SK
PROVIDER: S-EPMC6559794 | biostudies-literature | 2019 Apr
REPOSITORIES: biostudies-literature

Malin Steven K SK Kullman Emily L EL Scelsi Amanda R AR Godin Jean-Philippe JP Ross Alastair B AB Kirwan John P JP
Molecular nutrition & food research 20190320 7
<h4>Introduction</h4>The effect of whole-grain (WG) versus refined-grain (RG) diets on glucose-stimulated insulin secretion (GSIS) and β-cell function is unclear.<h4>Methods</h4>In a double-blind crossover randomized controlled trial, 13 prediabetic adults (37.2 ± 1.8 y, BMI: 33.6 ± 1.4 kg m<sup>-2</sup> , 2 h glucose: 146.9 ± 11.6 mg dL<sup>-1</sup> ) are provided isocaloric-matched WG and RG diets for 8-weeks each, with an 8-10 week washout between diets. Glucose, insulin, and C-peptide are st ...[more]