Extra virgin olive oil is one of the pillars of the Mediterranean Diet. In fact, this type of oil is not only a seasoning but a food rich in healthy benefits thanks to its antioxidant and anti-inflammatory properties. A research, published a few weeks ago in the Current Developments in Nutrition magazine by an American team from the Yale-Griffin Prevention Research Center (Njike et al, Jun 2020), showed that extra virgin olive oil, but not refined olive oil, is able to improve endothelial function, thus bringing benefit to the cardiovascular system.
The study is small, in fact it has recruited only 20 people with an average age of 56 years. In any case, even if it has this limit, the research is very interesting, let's see why. The study participants, after a week of controlled diet to avoid interactions with other foods, were divided into two groups. The first group consumed a meal prepared with 50 ml of refined olive oil, the second prepared with 50 ml of extra virgin olive oil. Compared to refined olive oil, extra virgin olive oil is richer in antioxidant polyphenols and anti-inflammatory substances. After two hours, the researchers analyzed the blood pressure and the endothelial function. The endothelium is a layer that lines the interior surface of the blood vessels, the lymphatic vessels and the heart. The function of the endothelium has been tested through the flow-mediated arterial dilatation, namely the dilatation of the artery when blood flow increases. No difference in blood pressure was observed in the two groups. Instead, in the group that had consumed the meal prepared with extra virgin olive oil the endothelial function had improved significantly compared to the other group, allowing to understand the benefits that extra virgin olive oil, but not the refined olive oil, brings to the cardiovascular system.