Diet rich in olive oil reduces chance of developing nearly all kinds of cancer
A diet in which olive oil is the main source of fat offers protection against nearly all sorts of cancer. This is suggested in a meta-analysis that Greek nutritionists published in 2011 in Lipids in Health and Disease.
The researchers tracked down 19 epidemiological studies - all case-controlled - which compared the olive oil intake of a total of 13,800 cancer patients with that of 23,340 cancer-free people. The Greeks collated all the data from the different studies and re-analysed it.
The researchers were not able to distinguish between the effect of using ordinary olive oil from that of using virgin olive oil. Nor were they able to say anything about which components of olive oil offer protection against cancer.
The figure below shows the effect of a relatively high olive oil intake versus that of a relatively low intake. Generally speaking, olive oil reduced the likelihood of developing cancer. The researchers found a lot of studies in particular that showed that olive oil protects against breast cancer.
The researchers found no usable studies on the effect of olive oil consumption on skin cancer, but they suspect that there is a relationship. "It could be stated that due to the high concentrations of squalene in olive oil, which is transferred to the skin, olive oil intake could be searched for a protective effect against skin cancer," they wrote.
"Evidence to support that olive oil conveys protection against occurrence of different types of cancer necessitates more epidemiological studies, especially prospective ones, specifically designed to address these issues, which would all adjust for total energy intake," the researchers concluded.
"The ongoing and future well designed cohort studies will help to further examine the association and questions arising, such as, firstly if olive oil intake facilitates more vegetable intake, thus, maximising its beneficial effects to cancer prevention, and secondly, if the possible beneficial effects of olive oil are attributed to its monounsaturated content or to its other components, could be addressed."
"Large enough and well conducted trials, both for countries with high as with low intake of olive oil, could be necessary, for the purpose of generalisability."
Largely unfounded speculations about the mechanism on our part
Olive oil contains oleuropein, which boosts the concentration of adrenalin. During physical exercise Natural Killer Cells destroy and clear up cancer cells - and they do that even more vigorously the more adrenalin there is circulating in the body.
Lipids Health Dis. 2011 Jul 30;10:127.
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