Olive oil has been proven to lower LDL (bad cholesterol) and raise HDL (good cholesterol) levels when used to replace saturated fat such as butter. It also contains beta carotene, vitamins A, E, D and K, plus many more healthful nutrients. Research shows these nutrients have beneficial effects on almost every bodily function.
Extra virgin olive oil has the lowest oxidation rate of cooking oils, meaning it is able to maintain its molecular structure when heat is applied. You want the lowest oxidation rate possible because oxidation promotes free radicals, chemicals that are highly reactive and damage cells. Some of this damage may lead to cancer and other disease states.
Extra virgin olive oil is also one of the best sources of antioxidants, which protect cells from damage and oxidation. Extra virgin olive oil also has an amazing skin- and body-protecting polyphenols called hydroxytyrosol. Studies show that hydroxytyrosol has among the greatest free-radical absorbing capacities.