TY - JOUR

T1 - Weight loss improves β-cell function independently of dietary carbohydrate restriction in people with type 2 diabetes: A 6-week randomized controlled trial

AU - Thomsen, Mads Norvin

AU - Skytte, Mads J

AU - Samkani, Amirsalar

AU - Astrup, Arne

AU - Fenger, Mogens

AU - Frystyk, Jan

AU - Hartmann, Bolette

AU - Holst, Jens Juul

AU - Larsen, Thomas Meinert

AU - Madsbad, Sten

AU - Magkos, Faidon

AU - Rehfeld, Jens Frederik

AU - Haugaard, Steen Bendix

AU - Krarup, Thure

N1 - Copyright © 2022 Thomsen, Skytte, Samkani, Astrup, Fenger, Frystyk, Hartmann, Holst, Larsen, Madsbad, Magkos, Rehfeld, Haugaard and Krarup.

PY - 2022

Y1 - 2022

N2 - Background: Carbohydrate restriction may benefit β-cell function and glucose metabolism in type 2 diabetes (T2D) but also leads to weight loss which in itself is beneficial.Methods: In order to determine the additional effect of carbohydrate restriction in addition to a fixed body weight loss, we randomly assigned 72 adults with T2D and obesity (mean ± SD HbA1c 7.4 ± 0.7%, BMI 33 ± 5 kg/m2) to a carbohydrate-reduced high-protein diet (CRHP; energy percent from carbohydrate/protein/fat: 30/30/40) or an isocaloric conventional diabetes diet (CD; 50/17/33) for 6 weeks. All foods were provided free of charge and total energy intake was tailored individually, so both groups lost 6% of baseline body weight. Results: Despite significantly greater reductions in HbA1c (mean [95% CI] -1.9 [-3.5, -0.3] mmol/mol) after 6 weeks, the CRHP diet neither improved glucose tolerance, β-cell response to glucose, insulin sensitivity, during a 4-h oral glucose tolerance test, nor basal proinsulin secretion when compared to the CD diet, but increased C-peptide concentration and insulin secretion rate (area under the curve [AUC] and peak) significantly more (~10%, P ≤ 0.03 for all). Furthermore, compared with the CD diet, the CRHP diet borderline increased basal glucagon concentration (16 [-0.1, 34]%, P = 0.05), but decreased glucagon net AUC (-2.0 [-3.4, -0.6] mmol/L ×240 min, P < 0.01), decreased basal triglyceride and total AUC (~20%, P < 0.01 for both), and increased gastric inhibitory polypeptide total AUC (14%, P = 0.01). Conclusion: A moderately carbohydrate-restricted diet for 6 weeks decreased HbA1c but did not improve β-cell function or glucose tolerance beyond the effects of weight loss when compared with a conventional diabetes diet in people with T2D. Clinical trials registration: www.Clinicaltrials.gov, Identifier: NCT02472951.

AB - Background: Carbohydrate restriction may benefit β-cell function and glucose metabolism in type 2 diabetes (T2D) but also leads to weight loss which in itself is beneficial.Methods: In order to determine the additional effect of carbohydrate restriction in addition to a fixed body weight loss, we randomly assigned 72 adults with T2D and obesity (mean ± SD HbA1c 7.4 ± 0.7%, BMI 33 ± 5 kg/m2) to a carbohydrate-reduced high-protein diet (CRHP; energy percent from carbohydrate/protein/fat: 30/30/40) or an isocaloric conventional diabetes diet (CD; 50/17/33) for 6 weeks. All foods were provided free of charge and total energy intake was tailored individually, so both groups lost 6% of baseline body weight. Results: Despite significantly greater reductions in HbA1c (mean [95% CI] -1.9 [-3.5, -0.3] mmol/mol) after 6 weeks, the CRHP diet neither improved glucose tolerance, β-cell response to glucose, insulin sensitivity, during a 4-h oral glucose tolerance test, nor basal proinsulin secretion when compared to the CD diet, but increased C-peptide concentration and insulin secretion rate (area under the curve [AUC] and peak) significantly more (~10%, P ≤ 0.03 for all). Furthermore, compared with the CD diet, the CRHP diet borderline increased basal glucagon concentration (16 [-0.1, 34]%, P = 0.05), but decreased glucagon net AUC (-2.0 [-3.4, -0.6] mmol/L ×240 min, P < 0.01), decreased basal triglyceride and total AUC (~20%, P < 0.01 for both), and increased gastric inhibitory polypeptide total AUC (14%, P = 0.01). Conclusion: A moderately carbohydrate-restricted diet for 6 weeks decreased HbA1c but did not improve β-cell function or glucose tolerance beyond the effects of weight loss when compared with a conventional diabetes diet in people with T2D. Clinical trials registration: www.Clinicaltrials.gov, Identifier: NCT02472951.

KW - Faculty of Science

KW - β-cell function

KW - Carbohydrate restriction

KW - Insulin Sensitivity

KW - Low-grade inflammation

KW - Type 2 diabetes

KW - Weight loss

U2 - 10.3389/fnut.2022.933118

DO - 10.3389/fnut.2022.933118

M3 - Journal article

C2 - 36061897

VL - 9

JO - Frontiers in Nutrition

JF - Frontiers in Nutrition

SN - 2296-861X

M1 - 933118

ER -