OLIVE OILS AND HEALTH 132 arterial hypertension). In comparison to the control group, participants in the intervention group—those who followed a Mediterranean diet supplemented with extra virgin olive oil (EVOO) for a year—showed an average reduction of 4 mmHg in systolic blood pressure and 1.9 mmHg in diastolic blood pressure, respectively. Although the figures seem small, a reduction of 3 mmHg in systolic pressure is associated with 8% and 5% reductions in stroke and coronary disease mortalities, respectively. Observational and short-term intervention studies have also demonstrated that EVOO consumption reduces blood pressure and, consequently, this promotes a reduction in the need for anti-hypertensive medication. Besides the health benefits provided by EVOO with its fatty acid profile and richness in polyphenols, the bitter taste of EVOO usually reduces salt consumption. EVOO oleic acid incorporates to cell membranes and reduces blood pressure by modifying cell signalling mechanisms. Several EVOO polyphenols, such as oleanolic acid and oleuropein, release nitric oxide into the vascular endothelium, thus, reducing calcium in smooth muscle fibres, promoting vasodilation and the corresponding reduction in blood pressure. - Effects on blood lipids Both dyslipidaemia (hypercholesterolemia and/or hypertriglyceridaemia) and postprandial hyperlipidaemia are key factors contributing to vascular risk. The ingestion of 25 mL of EVOO does not promote a rise in postprandial lipemia, whereas a similar intake of saturated or polyunsaturated fat (nuts) does. In a randomized intervention nutritional study, consumption of polyphenol-rich EVOO (250 – 1000 mL per day) significantly reduced plasma LDL cholesterol in women with osteopenia (mean age, 64 years). In another randomised study, with 47 healthy male participants, the ingestion of EVOO at 25 mL/day significantly increased HDL cholesterol. In this regard, the results of the EUROLIVE study are noteworthy. In this randomised, crossover, controlled study with 200 healthy male volunteers, three types of olive oils with similar composition, but with differences in their polyphenol content, were administered (25 mL/day) for 3 weeks. An increase in plasma HDL cholesterol (Figure 10.1), and a decrease in plasma oxidised LDL, were observed in a direct dose-dependent manner with the phenolic content of the olive oil administered. In the PREDIMED pilot study, including the first 722 participants, a significant rise in HDL-cholesterol and a decrease in LDL cholesterol, without changes in triglycerides, were observed in the intervention group with the Mediterranean diet and EVOO. After this intervention, plasma apolipoprotein (Apo) A1 increased and
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