The efficacy of polyunsaturated fatty acids for atherosclerotic diseases

In the field of anti-aging medicine and health science, various opinions about lipid and health are found. Among lots of clinical and epidemiological research, there has been a significant inverse association between intake of long-chain n-3 polyunsaturated fatty acids (PUFA) and atherosclerosis development [1,2]. These studies included docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and mortality rate with coronary artery diseases. There was also the Japan EPA Lipid Intervention Study (JELIS), which showed the efficacy of reduction of major coronary events [3]. It showed a 19% reduction in major coronary events by a primary endpoint in the EPA group compared with the control group. Regarding n-3 PUFA, there have been controversies concerning the effect of arteriosclerotic diseases. Formerly, it was rather widely known that the preventive arteriosclerotic effect was present in n-3 PUFA. However, recent papers showed opposite results. This problem is related to not only medical and health matter, but also our meals in our usual lives. In this article, the problem of the effect of n-3 PUFA will be described. The results of the ASCEND (A Study of Cardiovascular Events iN Diabetes) trial were announced and noted in 2018 [4]. The prevention effect of n-3 PUFA on arteriosclerosis was investigated by Randomized Comparison Test (RCT). The result was negative, which was contrary to the clinical effects previously reported. Formerly, there was a study suggested that fish intake could reduce heart diseases [5]. Later, clinical research has been developed concerning the relationship between lipids and arteriosclerotic diseases such as heart diseases. Under these circumstances, there are two reports in 2019 from the supreme medical journal, New England Journal of Medicine. Both results were contradictory, in which one showed a preventive effect in REDUCE-IT [6], and another did not show a preventive effect (VITAL) [7]. Details of these reports will be described in the following. There is a study of the Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial (REDUCE-IT). REDUCE-IT was an RCT study from 473 centers in 11 countries [6,8]. The subjects included patients with established cardiovascular diseases or with diabetes and other risk factors, who had been receiving statin therapy with elevated triglyceride and/or LDL-cholesterol level. In other words, the purpose was the check for the prevention of recurrence of arteriosclerotic events. Subjects (n=8,179) were divided into two groups, which