Scientists have discovered why eating a Mediterranean diet rich in fruits, vegetables and particularly olive oil can help to protect women from developing breast cancer. The key is oleic acid, the main component of olive oil. Dr Javier Menendez, of Northwestern University Feinberg School of Medicine in Chicago, said oleic acid blocks the action of a cancer-causing oncogene called HER-2/neu which is found in about 30 percent of breast cancer patients.Posted by Greg Ransom"We have something now that is able to explain why the Mediterranean diet is so healthy," Menendez told Reuters.