(Ivanhoe Newswire) -- Researchers know the Mediterranean diet seems to protect against breast cancer, and they now know the reason why. After running a series of laboratory experiments, researchers from the Northwestern University Feinberg School of Medicine in Evanston, Ill., discovered why a high intake of oleic acid-rich olive oil fights cancer.

Researchers found oleic acid dramatically cuts the levels of a gene called Her-2/neu. High levels of Her-2/neu are associated with aggressive tumors in many breast cancer patients. Additionally, researchers found oleic acid boosts the effectiveness of the antibody treatment trastuzumab (Herceptin), which targets Her-2/neu and helps prolong the life of breast cancer patients. Oleic acid was also found to increase the expression of a tumor suppresser protein.

Researchers emphasize it is important to be cautious about the implications of the study, as laboratory results do not always translate into clinical practice. However, they say the findings do suggest a higher level of oleic acid in breast tissue could provide an effective means of influencing the outcome of breast cancer patients who have high levels of Her-2/neu.

Researchers say, "Our findings underpin epidemiological studies that show the Mediterranean diet has significant protective effects against cancer, heart disease, and aging."

The Mediterranean diet includes consumption of whole grains, fruits, vegetables, nuts, and olive oil.