December 18, 2008

Extra-virgin olive oil may suppress cancer

Phenols present in extra-virgin olive oil drastically suppress overexpression of the cancer gene HER2 in human breast cancer cells, Spanish researchers said.

Javier Menendez from the Catalan Institute of Oncology and Antonio Segura-Carretero from the University of Granada in Spain led a team of researchers who found extra-virgin olive oil is the oil that results from pressing olives without the use of heat or chemical treatments. It contains phytochemicals that are otherwise lost in the refining process, the researchers said.

HER2-positive breast cancer is a breast cancer that tests positive for a protein HER2, which promotes the growth of cancer cells. Menendez and colleagues separated the oil into fractions and tested these against breast cancer cells in lab experiments. All the fractions containing the major extra-virgin phytochemical polyphenols -- lignans and secoiridoids -- were found to effectively inhibit HER2.

Although the findings, published in the journal BMC Cancer, provide new insights on the mechanisms by which good quality oil, polyphenol-rich extra-virgin olive oil, might contribute to a lowering of breast cancer risk in a HER2-dependent manner, extreme caution must be applied when applying the lab results to the human situation, the researchers said.

The active phytochemicals -- lignans and secoiridoids -- exhibited tumoricidal effects against cultured breast cancer cells at concentrations that are unlikely to be achieved in real life by consuming olive oil, the researchers said in a statement.