58th EASD Annual Meeting of the European Association for the Study of Diabetes

Background and aims: One of the major causes of mortality in type 2 diabetes (T2D) is cardiovascular disease (CVD). Endothelial dysfunction (ED) is an early sign of atherosclerosis which is present before overt clinical CVD. In non-diabetic subjects, low-carbohydrate diets (LCDs) have been demonstrated to improve vasodilatory reactivity in the endothelium, but in T2D patients, the effect of a LCD on measures of ED is mixed. The aim of this study was to examine the effect of a non-calorie-restricted LCD high in fat for six months on measures of ED in T2D. Materials and methods: Patients with T2D were randomized 2:1 to either a LCD with a max. of 20 E% (percentage of total energy intake) from carbohydrates and min. 50 E% from fat (n = 49) or a control diet with 50-60 E% from carbohydrates (n = 22) for 6 months. Both diets were non-calorie restricted. Flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation (NID) were assessed at baseline and after six months using B-mode ultrasound scans of the brachial artery and are reported as dilation in percentage (%). Blood samples were collected and dual-energy x-ray absorptiometry (DXA) and anthropometrics were assessed at baseline and after six months. We report baselines differences and the mean difference in change (MDIC) between groups from baseline to six months. Results: Participants on the LCD reduced their self-reported carbohydrate intake to ~ 14 E% and increased their fat intake to ~63 E% including a 2.7 fold increase in saturated fatty acids (SFA). The LCD caused a clinically relevant decrease in HbA1c (MDIC: -8.9 ± 1.7 mmol/mol; P < 0.001), a reduction in weight (MDIC: -3.9 ± 1.0 kg; P < 0.01) and improved body composition (P Conclusions: A non-calorie-restricted LCD high in fat for 6 months does not affect either FMD or NID in patients with T2D. While these results could not confirm a beneficial effect of LCD on ED as observed in non-diabetic individuals, the data also suggest that the higher intake of fat, in particular SFA, associated with a LCD, does not adversely affect endothelial function and hence cardiovascular risk in patients with T2D. Grant acknowledgement: Novo Nordisk Foundation, A. P. Møller Foundation