Which olive oil should you choose?

Spanish researchers have found anti-cancer chemicals in extra-virgin olive oil that may help explain the link between lower rates of breast cancer and diets rich in olive oil around the Mediterranean.

Extra-virgin olive oil, made by pressing olives without heat or chemical treatment, contains substances not found in refined olive oil. The researchers separated the components of extra-virgin oil and tested each on cancer cells in the lab. All the fractions containing polyphenols, such as lignans and secoiridoids, strongly suppressed HER2, a cancer gene active in some breast cancers. The results were published in BMC Cancer.

"Our study shows for the first time that all the major complex phenols in extra-virgin olive oil strongly suppress the HER2 cancer gene in human breast cancer cells," one of the researchers said.

These are lab results on cells, not proof that olive oil prevents or treats breast cancer, but they are another reason to choose extra-virgin olive oil as part of a healthy diet.