Compared with a low-fat diet, Mediterranean diets supplemented with olive oil or nuts have beneficial effects on cardiovascular risk factors.

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Abstract-The objective was to study oxidative status, antioxidant activities, and reactive oxygen species byproducts in whole blood and mononuclear peripherals cells and their relationship with blood pressure. Sixty-six hypertensive patients and 16 normotensive volunteers as a control group were studied. In both, whole blood and peripheral mononuclear cells oxidized/reduced glutathione ratio and malondialdehyde was significantly higher, and the activity of superoxide dismutase, catalase, and glutathione peroxidase was significantly lower in hypertensive patients when compared with normal subjects. The content of damaged base 8-oxo-2Ј-deoxyguanosine in nuclear and mitochondrial deoxyribonucleoproteins of hypertensive subjects was also significantly higher than that of the normotensive control subjects. No differences in these measurements were found among hypertensive subjects grouped in tertiles of 24-hour average mean blood pressure or between "white-coat" and established hypertensive subjects. Furthermore, no relationship was observed between the average of 24-hour mean blood pressure and oxidized/reduced glutathione ratio, reactive oxygen species byproducts, malondialdehide, or genomic 8-oxo-2Ј-deoxyguanosine. In whole blood and in mononuclear cells from hypertensive subjects, there was an increase in oxidative stress and a reduction in the activity of antioxidant mechanisms that appeared to be independent of the blood pressure values. Key Words: oxidative stress Ⅲ hypertension, renovascular Ⅲ hypertension, obesity Ⅲ risk factors Ⅲ antioxidants Ⅲ DNA O xidative stress, an excessive production of reactive oxygen species (ROS) outstripping antioxidant defense mechanisms, has been implicated in pathophysiological conditions that affect the cardiovascular system such cigarette smoking, hypercholesterolemia, diabetes, and hypertension. 1-3 Oxidative stress accompanying hypertension in animal models includes spontaneous hypertension, 4 renovascular hypertension, 5 deoxycorticosterone acetate-salt model, 6 and obesity-related hypertension. 7 Moreover, reducing superoxide radicals by infusion of superoxide dismutase (SOD) significantly decreases blood pressure in spontaneously hypertensive rats. 8 In humans, hypertension is also considered a state of oxidative stress that can contribute to the development of atherosclerosis 9 and other hypertension-induced organ damage. 10 Assessment of antioxidant activities and lipid peroxidation byproducts in hypertensive subjects indicates an excessive amount of ROS and a reduction of antioxidant mechanism activity in both blood as well as in several other cellular systems, 11 including not only vascular wall cells 12 but also those found in circulating blood. 13 Another consequence of the overproduction of ROS is the instability of critical nonlipidic macromolecules, which may have important consequences on cellular functions. Among these, genomic and mitochondrial DNA 14 are especially relevant. Up to now, however, no information concerning the damage of both types of DNA in ce...

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Background: Despite the richness in antioxidants of the Mediterranean diet, to our knowledge, no randomized controlled trials have assessed its effect on in vivo lipoprotein oxidation. Methods: A total of 372 subjects at high cardiovascular risk (210 women and 162 men; age range, 55-80 years), who were recruited into a large, multicenter, randomized, controlled, parallel-group clinical trial (the Prevenció n con Dieta Mediterránea [PREDIMED] Study) directed at testing the efficacy of the traditional Mediterranean diet (TMD) on the primary prevention of coronary heart disease, were assigned to a low-fat diet (n = 121) or one of 2 TMDs (TMDϩvirgin olive oil or TMDϩnuts). The TMD participants received nutritional education and either free virgin olive oil for all the family (1 L/wk) or free nuts (30 g/d). Diets were ad libitum. Changes in oxidative stress markers were evaluated at 3 months. Results: After the 3-month interventions, mean (95% confidence intervals) oxidized low-density lipoprotein (LDL) levels decreased in the TMD ϩ virgin olive oil (−10.6 U/L [−14.2 to −6.1]) and TMDϩnuts (−7.3 U/L [−11.2 to −3.3]) groups, without changes in the low-fat diet group (−2.9 U/L [−7.3 to 1.5]). Change in oxidized LDL levels in the TMDϩ virgin olive oil group reached significance vs that of the low-fat group (P =.02). Malondialdehyde changes in mononuclear cells paralleled those of oxidized LDL. No changes in serum glutathione peroxidase activity were observed.

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