Fish food, fish oil and cardiovascular disease.

During recent years there has been growing interest in the possibility that dietary fish confers some protection against ischaemic heart disease. In four prospective studies, people who ate moderate amounts of fish tend to have a lower mortality from heart disease than persons who ate little or no fish. A randomized controlled trial showed that mortality after myocardial infarction was less among men who were advised to increase their intake of fatty fish than in a control group. Studies of fish oil administered to volunteers suggest that it is the omega-3 fatty acids which are responsible. The effects of fish oil include a reduction in serum triglyceride concentration, a reduction in platelet activity, a reduction in blood pressure, and (in animals) prevention of arrhythmias. Some of these effects require doses much larger than those that would normally be supplied by dietary fish.