Aspirin and fish oil in cancer prevention

That aspirin may prevent, or regress, some early cancers has been suspected for some time. The British clinical trial on genetically susceptible individuals to bowel cancer (October 29) further confirms this protective action of aspirin. A 1982 Nobel Prize was awarded for the discovery of how very short-acting hormones in all our cell membranes, called eicosanoids, affect many body functions and how dietary factors and aspirin modify their action.

It was discovered that some eicosanoids reduced pain, thinned the blood, suppressed inflammation and inhibited cancer formation (“good” eicosanoids), while other eicosanoids (“bad”) did the opposite. It was also discovered that “bad” eicosanoids could be discouraged, and the “good” ones promoted, by both aspirin and fish oil, and that high blood insulin encouraged the “bad” ones. This explains how aspirin and fish oil thin the blood and reduce heart attack risk, and why the chronic high blood insulin of pre-diabetes (metabolic syndrome) increases risk of cardiovascular disease and risk of a number of cancers.

Fish oil is therefore, almost certainly, as effective a cancer-inhibiting agent as aspirin, with the added advantage that fish oil carries no risk of gastric ulcer/haemorrhage (and rarely asthma). Last year, the European Medicines Agency approved the designation of eicosapentaenoic acid (EPA) for use in familial adenomatous polyposis (FAP), an inherited condition leading to bowel cancer at a relatively young age. EPA is one of two fatty acids in fish oil which is now thought to be the effective agent (not DHA) against some cancers, heart attacks, depression and against some chronic inflammatory diseases. EPA’s designation as a medicinal product for FAP was based on demonstration of halting and regression of pre-cancerous bowel changes in an animal model.

Fish oil and aspirin therefore hold promise as preventive agents for some cancers and possibly also as post-surgical cancer recurrence preventive agents. The fish oil used should not be cod liver oil, which may contain heavy metal impurities, but should be a purified type, and ideally a pure EPA product, one of which is now available locally. One must also not forget that old American animal experiments showed that too much dietary animal protein promoted cancer development, and that human studies have consistently shown a connection between diets rich in fruits, vegetables and whole grains with diminished risk of some cancers, such as bowel, and possibly also diminished risk of post-surgical recurrence.