Omega-3 fatty acids and cardiovascular disease: new developments and applications

The omega-3 fatty acids (FA) found in fish oils, eicosapentaenoic and docosahexaenoic acids (EPA and DHA, respectively), have been extensively studied therapeutically in a wide variety of disease conditions, but in none more than cardiovascular disease (CVD). Our review summarizes mechanisms of action, recent meta-analyses of CVD outcome trials, sources (fish and supplements), and recommendations for use of omega-3 FA in clinical practice. With the ability to now measure the omega-3 FA biostatus through blood tests, patients can achieve cardioprotective levels by either taking fish oil supplements or simply eating more oily fish. Two omega-3 FA formulations (both in the ethyl ester form) have been approved by the US Food and Drug Administration (FDA) for the treatment of patients with very high triglyceride levels (> 500 mg/dL); one contains both EPA and DHA, whereas the other contains only EPA. The agents have been extensively tested in 2 patient populations, those with very high triglycerides and those with triglycerides between 200 and 500 mg/dL while on background statin therapy. In general, treatment with EPA+DHA appears to lower patient triglycerides more effectively, but in those patients with very high triglyceride levels, use of EPA+DHA also raised low-density lipoprotein cholesterol levels, whereas EPA alone did not. Both formulations, at doses that do not lower triglycerides, have been shown to reduce CVD events in some, but not all, studies. Given the favorable risk-to-benefit ratio for these essentially nutritional agents, use is expected to continue to expand.