Effects of short-term very-low calorie diet on islet β-cell function, glucose and lipid metabolism in type 2 diabetic patients

Abstract

Objective To study the effects of short-term caloric restriction (CR) on insulin secretion and glucose and lipid metabolism in type 2 diabetic patients.Methods Oral glucose tolerance test,insulin releasing test,and other biochemical tests were performed in 20 type 2 diabetic patients whose body mass index(BMI) was less than 40 kg/m2before and after 9 days with CR(300-600 kcal/d).Results (1) After short-term CR,the patients' mean body weight was reduced from (70.5 ± 11.0) kg to (65.9 ± 10.5) kg(P＜0.01),and their waist circumference from (86.68 ± 10.26) cm to (81.03 ± 9.77) cm (P＜0.001).Moreover,BM1 was reduced from (25.99 ± 2.78) kg/m2 to (23.89 ± 2.66) kg/m2 (P＜0.01),the visceral fat mass area decreased from (104.79 ± 29.65) cm2 to (97.44 ± 29.14) cm2 (P =0.015),and the weight of body fat mass was reduced from (22.8 ± 4.9) kg to (20.9 ± 4.5) kg(P＜ 0.01).(2) After 9 days of CR,there were significant reductions in fasting blood glucose [from (8.47 ± 1.77) mmol/L to (6.30± 1.82) mmol/L,P＜0.01],fasting insulin [from (10.8±4.0) mIU/L to (7.1 ±4.2) mIU/L,P＜ 0.01),and blood triglyceride [from (2.36 ± 1.71) mmol/L to (1.28 ± 0.50) mmol/L,P＜0.05),as well as lowering of systolic blood pressure[from (127 ± 11) mmHg(1 mmHg=0.133 kPa) to (117 ± 10) mmHg,P＜0.01),and diastolic blood pressure [from (80 ± 7) mmHg to (73 ± 10) mmHg,P＜0.01],though,no significant difference was found in total eholesterol and low density lipoprotein levels before and after CR.(3) The first-phase insulin response,which was represented by acute insulin response,was increased from (62.37 ± 40.28) mIU/L to (98.1 8 ± 77.17) mIU/L(P＜0.05) during the study period,while changes in insulin area under the curve showed no significant differences before and after CR.HOMA-IR,which was a parameter of insulin resistance,was decreased from 4.12 ± 1.87 to 2.02 ± 1.25 (P＜0.01).Conclusion Short-term CR can effectively improve islet β cell function,glucose and lipid metabolism in patients with type 2 diabetes. Key words: Caloric restriction ; Diabetes mellitus, type 2 ; Insulin secretion ; Glucose ; Lipid