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. Oleic acid in fact, is able to down-regulate the most important oncogene in breast cancer and Olive oil is the most important source of oleic acid. They found that oleic acid not only suppressed the action of the oncogene, it also improved the effectiveness of the breast cancer drug Herceptin. Oleic acid suppressed the gene, and other tests showed that it boosted an antibody treatment trastuzumab (Herceptin), which targets the gene and has helped to prolong the lives of many breast cancer patients.

More than one million cases of breast cancer are diagnosed worldwide each year. In 1998 alone, the disease caused 1.6 percent of all female deaths.