10.31 Habitual Dietary Antioxidant Intake, Flow Mediated Dilation and Augmentation Index in Hypertensive Patients and Normotensive Controls

Introduction: Essential hypertension is characterised by early vascular alterations such as endothelial dysfunction, increased arterial stiffness and wave reflection. Since these alterations are, at least in part, mediated by increased oxidative stress, the aim of the study was to evaluate the possible association of daily dietary intake of the 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 questionnaires in 200 untreated HT patients and 130 NT subjects (age range:22–73 years). Brachial artery endothelium-dependent (as flow mediated dilation, FMD) and -independent response (by sublingual glyceryl trinitrate, GTN, 25 μg) were assessed by high ultrasound ultrasounds and computerised analysis (automatic edge detection system) of brachial artery diameter modifications (maximal percentage increase in diameter). Augmentation index (AI) was determined with radial applanation tonometry (Sphygmoco®), as an index of arterial stiffness and peripheral wave reflection.

Results: The estimated dietary intakes of vitamin C was similar in HT patients and NT subjects (median 146.4 ± 68.7 mg/day and 149.1 ± 84.0 mg/day, respectively). The intake of vitamin E was also similar (median 8.68 ± 2.7 mg/day and 8.63 ± 2.9 mg/day, respectively). These intakes were in agreement with those commonly consumed in a general Italian population. FMD resulted significantly lower (5.0 ± 2.5 vs 6.2±2.7; p<0,05).

Conclusions: This cross-sectional study showed no association among levels of habitual dietary intake of selected antioxidants and peripheral parameters of endothelial function, arterial stiffness and wave reflection in a population of untreated HT.