The researchers investigated the anti-HER-2 effects of specific phytochemicals, referred to as polyphenols, which were directly extracted from extra virgin olive oil (EVOO) in cultured human breast cancer cell lines. The ability of EVOO to kill both HER-2 positive and negative tumors were then investigated.

Menendez and his co-workers found that all the major EVOO polyphenols (i.e. secoiridoids and lignans) induced tumor killing effects by selectively triggering high levels of programmed cell death (aptoposis) in cells over expressing HER-2.

The researchers concluded that EVOO derived polyphenols significantly  affect  breast  cancer  cell  proliferation and survival through a mechanism involving, at least in part, a significant down-regulation of HER2 expression and  activity. These results, together with the fact that humans have safely been ingesting polyphenols from olive oil for as long as they have been consuming olives and olive oil, support the notion that EVOO may offer potential benefits for HER-2 breast cancer. However the researchers also mention that although EVOO-rich  has  been  linked with  reduced  breast  cancer  risk, important  issues  such  as  whether the EVOO-derived secoiridoids and lignans are able to reach  tumor tissues should be carefully addressed  in  animal and  human  studies.  Only  then is it possible to confirm whether the anti-cancer benefits of EVOO phytochemicals are able to provide a new treatment approach in the management of HER2-positive breast cancer.

A/Professor John Boyages, Director of the Westmead Breast Cancer Institute cautioned that, “although these results add to the evidence supporting a role for olive oil in health, it is unlikely that we will see the current therapies used in women with HER-2 positive breast cancer replaced by antioxidant components in the near future” but it’s another big piece in a complex puzzle we must research”

At the very least, studies such as these add to the known benefits of plant based diets in terms of cancer prevention. It’s also possible that other phytochemicals contained in different fruits and vegetables have similar specific effects, so the old adage to consume a wide variety of fruits and vegetables still holds true”, added Kellie Bilinski, Dietitian at the Westmead Breast Cancer Institute. 

Reference List   (1)   Menendez JA, Vazquez-Martin A, Garcia-Villalba R, Carrasco-Pancorbo A, Oliveras-Ferraros C, Fernandez-Gutierrez A et al. Anti-HER2 (erbB-2) oncogene effects of phenolic compounds directly isolated from commercial Extra-Virgin Olive Oil (EVOO). BMC Cancer 2008; 8(1):377.