Olive oil seems to protect against bowel cancer, according to research in 28 countries.
Researchers analyzed information from databases from the International Agency for Research in Cancer (IARC), detailing the rates of cancer for a five-year period, as well as food supply data from the Food and Agricultural Organization of the United Nations. Details of olive oil consumption were obtained from the International Olive Oil Council. Information on food and bowel cancer patterns was gathered for 28 countries, including most of Europe, the United Kingdom, the United States, Brazil, Colombia, Canada, and China.
The Diet Connection to Bowel Cancer
More than three-quarters of the difference in rates of bowel cancer among the different countries studied was explained by three dietary factors. Meat and fish combined were associated with an increased risk; a diet rich in olive oil was associated with a decreased risk. A diet high in meat, rather than one low in cereals and vegetables, seemed to be critical, the research showed. The protective effect of olive oil remained, regardless of the amount of fruit and vegetables in the diet.
The authors explain that a high meat intake increases the amount of a bile acid called deoxycyclic acid, which reduced the activity of an enzyme, diamine oxidase (DAO). DAO is thought to regulate cell turnover in the bowel lining. Its reduction might therefore be important in abnormal cell turnover. Olive oil, on the other hand, seems to reduce the amount of bile acid produced and to increase DAO levels.
How Does Olive Oil Fight Cancer?
Dr. Chris Gill, a researcher at the University of Ulster, says the beneficial nature of the "Mediterranean diet" – a diet rich in olive oil – is already well known in scientific circles. Dr. Gill and other researchers at UU conducted an in vitro (in a test tube) experiment to take that knowledge a step further. Their research is looking for the exact mechanisms by which olive oil reduces the risk of cancer.
"Because the colon is one of the major cancer sites thought to be protected by olive oil, our research team has studied the potential anti-cancer effects of virgin olive chemical compounds in cultured cells that are widely used as study models for colorectal cancer," said Dr Gill. "We found that incubation of one cancer cell line with increasing concentrations of olive oil phenols for 24 hours protected the cells from DNA damage."
After 48 hours of exposure to olive oil phenols on another in vitro cell line, Dr. Gill saw that the olive oil exerted what he called an "anti-promoter effect in the carcinogenesis pathway" – that is, it seemed to stop the growth of cancer cells. He acknowledged that the next stage is to test these findings in an animal study. |
