P.002 Habitual Antioxidant Vitamin Intake, Augmentation Index and Flow Mediated Dilation in Hypertensive Patients and Normotensive Controls

Abstract

Objective

We evaluated the association of daily dietary intake of antioxidants vitamins C and E with augmentation index and endothelial function in untreated essential hypertensive (HT) patients and normotensive (NT) subjects.

Methods

Dietary intake of major nutrients, total caloric intake and antioxidant vitamins were assessed with the Italian EPIC questionnaire in 200 untreated HT patients and 130 NT subjects. Augmentation index (AIx) was determined with radial applanation tonometry. Endothelium-dependent response was assessed as flow mediated dilation (FMD) of the brachial artery by high resolution ultrasounds and computerized analysis (automatic edge detection system) of brachial artery diameter modifications.

Results

AIx was significantly higher in HT patients (26.9 ± 9.6%) as compared to NT subjects (20.4 ± 11.3%), whereas FMD resulted significantly lower (5.0 ± 2.5 vs 6.2 ± 2.7; p<0.001). Calculated intake of vitamic C and E was similar in HT patients and in NT subjects (Vitamin C median 146.4 ± 68.7 mg/day and 149.1 ± 84.0 mg/day, Vitamin E median 8.68 ± 2.7 mg/day and 8.63 ± 2.9 mg/day, respectively). Multivariate analyses were controlled for smoking, physical activity status and total caloric intake. In both groups, levels of Vitamin C or E intake were not significant predictors for AIx. Finally, in both groups, levels of Vitamin C or E intake were not significant predictors for FMD.

Conclusions

No association exists between normal levels of regular food antioxidant intake, augmentation index and endothelial function in untreated essential hypertensive patients and normotensive subjects. This suggests that supplementation with vitamin C and E is necessary to show an effect on vascular function in this population.