A recent large study of 2500 participants (mean age 66 years, 54% women), a higher Omega-3 Index was associated with significantly lower risks for total mortality, for non-CVD and non-cancer mortality, and for total CVD events. Those in the highest omega 3 levels compared to those in the lowest had a 34% lower risk for death from any cause and 39% lower risk for incident CVD. These associations were generally stronger for docosahexaenoic acid than for eicosapentaenoic acid. When total cholesterol was compared it was not significantly related with the health outcomes.
Early studies in the 1980s investigating Greenland Eskimos began the research into the benefits of the omega 3 fatty acids. In Greenland, the fatty acid intake from seafood is high and there is a lower prevalence of autoimmune and inflammatory conditions. Omega 3 has been shown in many studies to help inhibit and even reverse inflammation. The omega 3 fatty acids found in walnuts, flaxseed, butternuts, and fish oils have anti-inflammatory properties, decreasing the amount of arachidonic acid in cell membranes.
Several recent studies have linked higher blood levels and/or dietary intakes of the long-chain n-3 polyunsaturated fatty acids (PUFAs) with greater longevity. Blood omega 3 levels were inversely associated with total mortality rates in the Cardiovascular Health Study, and similar results were seen in the Heart and Soul Study. Consistent with this, there is an inverse relationship between the Omega-3 Index and the rate of telomere attrition, a marker of cellular aging.
Omega 3 fatty acids work through a number of mechanisms, each having different effects, to reduce inflammation. As well recent studies suggest that some of the beneficial effects of fish oil are due, in part, to their antioxidant benefit.