NEW YORK: Certain micronutrients contained in olive oil and other foods could be responsible for the Mediterranean diet’s well known heart-healthy effects, Spanish researchers report.

These compounds, known as phenols, have been shown in laboratory studies to have antioxidant, anti-inflammatory and blood clot preventing powers, Dr Francisco Perez Jimenez of the Hospital Universitario Reina Sofia in Cordoba and colleagues write.

Their study is the first to show a benefit for phenol-rich olive oils on blood vessel function.

“The intake of food high in phenols compounds could improve cardiovascular health and protect the heart,” Jimenez told Reuters Health. “An example of these foods is virgin or extra virgin olive oil.”

Jimenez and his team compared the effect of consuming phenol-rich olive oil or olive oil with most of its phenol content removed in a group of 21 volunteers with high cholesterol.

The researchers measured the ability of the study participants’ blood vessels to respond to rapid changes in blood flow after they had consumed a relatively high-fat meal containing either type of olive oil. Blood vessels have been shown to function poorly after a high-fat meal.

Blood vessel response and function was improved for the first four hours after the high-phenol olive oil meal, the researchers found, but there was no difference in blood vessel function before and after volunteers ate the low-phenol olive oil meal.

The researchers also found increased levels of the blood vessel dilating molecule nitric oxide and reduced levels of oxidative stress after consumption of the high-phenol meal.

Consumers should reach for olive oils labelled “virgin” or “extra virgin,” which have the highest phenol content, Jimenez said.

He and his colleagues suggest that phenols’ antioxidant effects, as well as their ability to help the body use nitric oxide more effectively, could be responsible for their effects.

SOURCE: Journal of the American College of Cardiology, November 15 2005.—Reuters