By Pu Zhaohe

In recent years, with increasing craze of "fish oil" in Europe and America, this imported health product attracts some of the Chinese consumers. Fish oil is considered to be functioning as 1. regulating blood lipid metabolism, decreasing blood lipid level, and reducing the accumulation of lipid on the wall of vessels; 2. dilating vessels, increasing blood circulation, and lowering blood pressure; 3. decreasing the blood viscosity, and thus improving circulation; 4. depressing platelet aggregation to prevent embolism.

Meanwhile, medical specialists in various countries reported the experimental studies, showing that the results were so contradictory that American Heart Association had been forced to announce in 1997 that the association was not going to recommend the product to consumers due to its uncertainty.

In recent years, studies on a large population showed the undetermined therapeutic result of fish oil. Reduced risk of embolism requires administering larger amount of fish oil, while use of 30-80mg aspirin can have a better result. Dutch scientist confirmed that administration of fish oil did reduce the mortality of total population and patients with coronary heart disease (CHD), however, the incidence of nonfatal myocardial infarction (MI) was unchanged. Two American studies indicated that there was no correlation between the administration of fish oil and the incidence of MI.

Previous study reveals the improvement of lipid level in patients with hyperlipimia. But this result could not be confirmed by clinical trial ---unchanged mortality of CHD. Controversy regarding the effect of using fish oil on the preventing formation of plaque in the vessel still exited. Study demonstrates: a high dose of fish oil could prevent the diet-induced arteriosclerosis in　animal model, but in human being. In an American study, 31 patients with CHD determined by coronary angiography. The result showed that after a two-year period of administration of fish oil, patients' arteriosclerosis remained unchanged. Canadian and American scientists found that fish oil even revealed harmful effect which facilitated low density lipoprotein (LDL-C) easily to be oxidized, resulting in deposit of oxidized LDL-C in the vessel, gradually causing occlusion of coronary artery, MI or brain vessel accident.

Based on the recent studies, specialists indicated that fish oil may reduce the mortality of patients with CHD, while its effects on reduced risk for embolism, formation of vessel plaque, hyperlipimia were uncertain. Therefore, to determine the therapeutic effects of fish oil on treatment of hypertension, CHD, hyperlipimia, embolism needs further experimental and clinical studies.