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A Whole‐Grain Diet Increases Glucose‐Stimulated Insulin Secretion Independent of Gut Hormones in Adults at Risk for Type 2 Diabetes
Author(s) -
Malin Steven K.,
Kullman Emily L.,
Scelsi Amanda R.,
Godin JeanPhilippe,
Ross Alastair B.,
Kirwan John P.
Publication year - 2019
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.201800967
Subject(s) - medicine , endocrinology , insulin , ghrelin , crossover study , type 2 diabetes , prediabetes , peptide yy , incretin , gastric inhibitory polypeptide , hormone , meal , diabetes mellitus , chemistry , glucagon , receptor , placebo , alternative medicine , pathology , neuropeptide y receptor , neuropeptide
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‐peptide 0‐240 /Glc 0‐240 , 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.