Evidence from experimental studies suggests that the long-chain ω-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid have beneficial effects that may lead to reduced mortality from chronic diseases, but epidemiologic evidence is mixed. Our objective was to evaluate whether intake of long-chain ω-3 fatty acids from diet and supplements is associated with cause-specific and total mortality.

Study participants (n = 70,495) were members of a cohort study (the Vitamins and Lifestyle Study) who were residents of Washington State aged 50-76 years at the start of the study (2000-2002). Participants were followed for mortality through 2006 (n = 3,051 deaths).

Higher combined intake of eicosapentaenoic acid and docosahexaenoic acid from diet and supplements was associated with a decreased risk of total mortality (hazard ratio (HR) = 0.82, 95% confidence interval (CI): 0.73, 0.93) and mortality from cancer (HR = 0.77, 95% CI: 0.64, 0.92) but only a small reduction in risk of death from cardiovascular disease (HR = 0.87, 95% CI: 0.68, 1.10).

These results suggest that intake of long-chain ω-3 fatty acids may reduce risk of total and cancer-specific mortality.