 The relative paralysis of our arteries for hours after eating fast food and cheesecake may also occur after olive oil. Olive oil was found to have the same impairment in endothelial function as the rest of these high-fat meals. Sausage, egg, McMuffin was the worst, but olive oil wasn't far behind. Studies that have suggested endothelial benefits after olive oil consumption have measured something different, ischemia induced as opposed to flow-mediated dilation, and there's just not good evidence that that's actually an index of endothelial function, which is what predicts heart disease. Hundreds of studies have shown that this other test can give a false negative result. But it's not just olive oil. Other oils have also been shown to have deleterious effects. A significant constant decrease in endothelial function is three hours after each meal, independent of the type of oil, or whether the oil was fresh or deep-fried. Olive may be better than Omega-6, rich oils, or saturated fats, but still showed adverse effects. But this study was done on regular, refined olive oil. What about extra virgin? Extra virgin olive oil retains a fraction of the anti-inflammatory phytonutrients found in the olive fruit, and so it does not appear to induce the same kind of spike in inflammatory markers caused by regular olive oil. But what does that mean for our arteries? Extra virgin olive oil may have more of a neutral effect compared to butter, which exerted a noxious effect that lasted up to six hours, basically right up to the next meal. In the largest perspective study ever to assess the relationship between olive oil consumption and cardiac events, like heart attacks, there was a suggestion that virgin olive oil may be better than regular olive oil, but neither was found to significantly reduce heart attack rates after controlling for healthy dietary behaviors like vegetable intake, which tends to go hand in hand with olive oil intake. There have been studies, though, showing even extra virgin olive oil. Contrary to expectations, may significantly impair endothelial function as well. So, why does some study suggest people's endothelial function improves on Mediterranean diet? A diet rich in olive oil? Perhaps because it's also rich in whole grains, fruits, vegetables, beans, walnuts as well. Dietary fruits and vegetables appear to provide some protection against the direct impairment on endothelial function produced by high-fat foods, including olive oil. So, improvements in health may be in spite of, rather than because of the oil. In terms of their effects on post-prandial endothelial function, after a meal, the beneficial components of the Mediterranean diet may primarily be the antioxidant-rich foods, vegetables, fruits, and their derivatives, such as balsamic vinegar. Just adding some vegetables to a fatty meal may partially restore arterial function and blood flow.