Cancer is one of the chief causes of death in the developed countries, and its incidence is on the increase.

It is now conceded that there is a relationship between diet and the development of a large number of malignant tumours. Cell oxidation is one of the major risks in the formation of cancer: the more susceptible the cell is to oxygen, the greater the risk of cancer.

The types of cancer most closely associated with diet are colon-rectal, prostate and breast cancer.

Recent research has revealed that the type of fat seems to have more implications for cancer incidence than the quantity of fat.

What is cancer?
Olive oil and cancer

A tumour is an abnormal swelling or enlargement of a part of body tissue. Tumours may be benign or malignant.

Benign tumours are tumours whose cells remain at their original site. They form a localised cell mass which, when it grows, encapsulates and very rarely causes death.

Malignant or cancerous tumours, on the other hand, invade the tissue where they grow. Often they pass into the bloodstream and the lymphatic system, forming secondary tumours at other sites known as metastases. The speed of growth and metastasis varies according to the type of tumour.

Various environmental factors (physical factors: radiation; chemical factors: certain constituents of foods) and genetic factors are at play in the formation of tumours. In most types of cancer, environmental factors are most important.

Epidemiological studies suggest that olive oil exerts a protective effect against certain malignant tumours (breast, prostate, endometrium, digestive tract, …).

A number of research studies have documented that olive oil reduces the risk of breast cancer. Eating a healthy diet with olive oil as the main source of fat could considerably lower cancer incidence. The reason is that the cell mutations caused by cancer are partly due to toxins which, when consumed through the diet, attack DNA. On passing through the liver, these toxins produce free radicals that then attack DNA. To combat such free radicals, the body needs vitamins and antioxidants like those contained in olive oil.

It has also been reported that an olive-oil-rich diet is associated with reduced risk of bowel cancer. The protective effect of olive oil is irrespective of the amount of fruit and vegetables eaten in the diet.

Recent studies have demonstrated that olive oil provides protection against cancer of the colon. Lately, research has been looking into the metabolic implications of fats, more specifically the protective role of olive oil in chronic liver disease and in the disorder of the intestines known as Crohn's disease. Results point to beneficial effects of olive oil on pre-cancerous lesions. After analysing three types of diet, research scientists arrived at various conclusions. The olive oil diet reduced the number of cancerous lesions; the number of tumours that developed was clearly and significantly low; and the tumours were less aggressive and had a better prognosis.

This beneficial effect could be related to oleic acid, the predominant monounsaturated fatty acid in olive oil. It has been observed that this fatty acid lowers the production of prostaglandins derived from arachidonic acid, which in turn plays a significant part in the production and development of tumours.

However, it is not excluded that other constituents of olive oil, such as antioxidants, flavonoids, polyphenols and squalene may also have a positive influence. Squalene is believed to have a favourable effect on the skin by reducing the incidence of melanomas.

Olive oil also adds to the taste of vegetables and pulses whose benefits in cancer prevention have been amply proved.

Some very promising, current research is centred on the protection provided by olive oil against child leukaemia and various cancers, such as oesophageal squamous cell cancer.

Much has still to be discovered about how olive oil affects cancer and concrete data are still lacking on the mechanisms behind the beneficial role it plays in the prevention or inhibitionof the growth of different types of cancer. However, according to the information available at present, olive oil could actsimultaneously during the different stages involved in the process of cancer formation.