Scientists are still trying to discover why those who eat a Mediterranean diet seem to be less likely to develop breast cancer, and now they have a new clue – olive oil.

Spanish researchers have discovered that extra-virgin olive oil contains anti-cancer ingredients known as phytochemicals.

The chemicals are only present in olive oil that is considered “extra virgin,” meaning that it has not been refined using heat or chemical treatments.

To reach their conclusion, lead researcher Javier Menendez of the Catalan Institute of Oncology and colleagues analyzed different ingredients found in the oil, comparing how they interacted with breast cancer cells in the lab.

“Our findings reveal for the first time that all the major complex phenols present in extra-virgin olive oil drastically suppress overexpression of the cancer gene HER2 in human breast cancer cells,” he said.

However, the authors cautioned that although the results may have been conclusive in the lab, they might not be so straightforward in real life.

Many people already use olive oil as one of their health resources to support a healthy cardiovascular system.