Studies indicate that olive oil may be useful in lowering your blood pressure as part on an overall blood pressure diet. The Mediterranean diet, rich in olive oil, has been found to be associated with lower levels of serum lipids and blood pressure. The replacement of saturated fats and trans fats by monounsaturated fats is associated with a significant reduction in coronary heart disease.
A study conducted at the University of Barcelona explored the effects of olive oil consumption on lipid profile and blood pressure in men from Mediterranean regions (Italy and Spain) and men from non-Mediterranean regions (Finland, Denmark and Germany). The men received 25 ml olive oil per day with 3 different phenolic levels. The scientists found that the intake of olive oil for 9 weeks increased plasma oleic acid levels by 2 to 3% and decrease systolic blood pressure in non-Mediterranean men. No changes in blood pressure or oleic acid level were found in Mediterranean men, probably due to their habitually high intake of olive oil.
The authors concluded that a moderate consumption of olive oil may reduce systolic blood pressure of healthy men who do not typically consume a Mediterranean diet, but that larger trials are needed for confirmation.
Source: Bondia-Pons I, Schröder H, Covas MI, Castellote AI, Kaikkonen J, Poulsen HE, Gaddi AV, Machowetz A, Kiesewetter H, López-Sabater MC. Moderate consumption of olive oil by healthy European men reduces systolic blood pressure in non-Mediterranean participants. J Nutr. 2007 Jan;137(1):84-7