Key to the Mediterranean Diet's Ability to Reduce Breast Cancer Risk

Olive oil may be the key reason that eating a Mediterranean diet reduces breast cancer risk, suggests a laboratory study published in the Annals of Oncology. Oleic acid, the main monounsaturated fatty acid in olive oil, has been shown to reduce the expression of the Her-2/neu oncogene, which is associated with the aggressive growth of carpet cleaners helston breast cancer tumors. High levels of Her-2/neu are found in one-fifth of breast cancers, especially those that are resistant to treatment.

In this study, when Menendez and his colleagues from Northwestern University in Chicago exposed two strains of aggressive breast cancer cells to oleic acid, levels of Her-2/neu dropped 46%. When they combined oleic acid with lower levels than are normally used of Herceptin, a drug used to treat breast cancer, oleic acid greatly enhanced the effectiveness of the drug, dropping Her-2/neu expression as much as 70%. The end result: oleic acid promoted the apoptotic cell death (suicide) of aggressive, treatment resistant breast cancer cells.

A human study adds to the evidence that olive oil is a key factor in the lowering of breast cancer risk associated with a Mediterranean diet. Results of this two-year long study involving 755 women in the Canary Islands suggest that monounsaturated fat and, specifically, olive oil exert a protective effect against breast cancer.

Study participants consuming the most monounsaturated fat were found to have a 48% lower risk of breast cancer compared to women whose intake of monounsaturated fat was lowest.

Among women consuming the most olive oil, specifically, the risk of breast cancer was even lower. Compared to those consuming the least olive oil, women whose daily intake of olive oil was at least 8.8 grams, the equivalent of just .65 tablespoon/day, had a 73% lower risk of breast cancer risk!