Scientists have discovered that extra-virgin olive oil and an olive-rich diet contains plant chemicals that can help to combat breast cancer.
Researchers from the Catalan Institute of Oncology in Girona and the University of Granada separated olive oil into "fractions" containing different plant chemicals, which were then tested for their effects on breast cancer cells in a laboratory.
Extra-virgin olive oil is made from pressing olives without the use of heat or chemical treatments.
The scientists, led by Dr Javier Menendez and Dr Antonio Segura-Carretero, discovered that chemicals found in extra-virgin olive oil suppressed the breast cancer-promoting gene HER2.
Dr Sarah Cant, policy manager at the charity Breakthrough Breast Cancer, said the research was "interesting."
She added: "It will be interesting to see if further research in this area may lead to the development of new breast cancer treatments."
However, the scientists warned that the findings "should be treated with caution" due to the highly-concentrated levels of extra-virgin olive oil they used in their research.
They wrote in the online open access journal BMC Cancer: "The active phytochemicals exhibited tumoricidal effects against cultured breast cancer cells at concentrations that are unlikely to be achieved in real life by consuming olive oil."