The Effect of Vitamin C on Endothelial Function of Children with Type 1 Diabetes: An Experimental Study

Background: Considering the importance of improvement of endothelial function in patients with type 1 diabetes mellitus (DM) and to prevent its related micro‑ and macro‑vascular complications; in this study, the effect of vitamin C administration on improving endothelial function of children with type 1 diabetes was investigated. Methods: In this analytic‑experimental study, children with type 1 DM aged 6-18 years and a group of healthy children enrolled. Vitamin C (250 mg/daily) administrated for the two studied groups for 1‑month. Endothelial function evaluated by flow‑mediated dilatation (FMD) and intima‑media thickness (IMT) measurement using vascular Doppler ultrasonography, before and after trial. Results: In this study, 18 patients with type 1 diabetes (DM) and 19 normal children as the control group were studied. After vitamin C administration IMT reduced in all studied groups (P < 0.05). FMD increased in all studied groups, but it was significant only in the control group (P=0.02 in the control group and P=0.07 in patients with DM). Mean differences of IMT 2 – IMT 1, FMD 2 – FMD 1 and left ventricular (LV) mass 2 – LV mass 1 and blood pressure (BP) were not significantly different in two studied groups (P>0.05). Mean differences of IMT 2 – IMT 1, FMD 2 – FMD 1, LV mass 2 – LV mass 1 and BP were not significantly different in patients with HbA1c ≤7 g/dl and those with HbA1c >7 g/dl and control group (P>0.05). Conclusions: The findings of the current study indicated that vitamin C may have a protective effect on endothelial dysfunction, but regarding its effectiveness among the high‑risk population such as diabetic patients with and without appropriate glycemic control the study was not sufficiently powered due to its small sample size.