By Lisa Rapaport (Reuters Health) – A traditional Mediterranean diet with added olive oil may be tied to a lower risk of heart disease at least in part because it helps maintain healthy blood flow and clear debris from arteries, a Spanish study suggests. “A Mediterranean diet rich in virgin olive oil improves the function of high-density lipoproteins, HDL, popularly known as `good’ cholesterol,” said lead study author Dr. Alvaro Hernáez of the Hospital del Mar Medical Research Institute in Barcelona. This type of diet typically includes lots of fruits and legumes that are rich in antioxidants as well as plenty of vegetables, whole grains and olive oil.