Olive oil seems to protect against cancer

Olive oil, diet and colorectal cancer: an ecological study and an hypothesis 2000; 54: 756-60

Olive oil seems to protect against bowel cancer, suggests research involving 28 countries in the Journal of Epidemiology and Community Health.

Researchers analysed information from databases from the International Agency for Research in Cancer (IARC), detailing the rates of cancer for the years 1987 to 1992, as well as food supply data from the Food and Agricultural Organisation 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 UK, the USA, Brazil, Colombia, Canada, and China.

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, irrespective 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 reduces the activity of an enzyme, diamine oxidase (DAO). DAO is thought to regulate cell turnover in the bowel lining, and its reduction may 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.

Contact:

Dr Michael Goldacre, Unit of Health-Care Epidemiology, Department of Public Health, Institute of Health Sciences, University of Oxford. michael.goldacre@dphpc.ox.ac.uk