Micronutrients contained in olive oil and other foods could explain the health effect of the so-called Mediterranean diet. Researchers in Spain say phenols have antioxidant, anti-inflammatory and anti- clotting characteristics and their work is the first to show a beneficial effect on blood vessel function. Dr Francisco Perez Jimenez and colleagues at the Hospital Universitario Reina Sofia in Cordoba 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. They say vessel response and function improves in the first four hours after a high-phenol olive oil meal, but shows no difference after the low-phenol meal, and note that the high-phenol meal is also associated with increased levels of nitric oxide in the blood, and reduced levels of oxidative stress.