The long-awaited results of a major randomized human clinical trial involving 18,645 participants were published in the March 31, 2007 issue of The Lancet. In the JELIS Trial, Japanese participants were given either a statin drug alone or a combination of statin drug plus 1,800 mg of EPA daily from fish oil concentrate in three divided doses. After 4.6 years of follow-up, significant reduction in major coronary events (-19%) and unstable angina (-24%) were observed for participants in the fish oil/statin group compared to those in the statin only group. Total cholesterol and LDL cholesterol levels were reduced by 19% and 26% in both groups, respectively, but neither decrease was related to a risk reduction.
A subgroup analysis of 3,664 participants with a prior history of Coronary Artery Disease (CAD) showed significant reductions in major coronary events (-19%) and unstable agnina (-28%). A subgroup analysis of the 14,981 participants without prior CAD (primary prevention subgroup) showed a notable but non-significant reduction in major coronary events via a reduction in coronary death, heart attack, non-fatal coronary events, and unstable angina.
The researchers hypothesize that fish oil provides its protective benefits though a non-lipid mechanism. It is their belief that fish oils may help to stabilize atherosclerotic plaques via a reduction in plaque-bound macrophages while also providing anti-inflammatory, antiarrhythmic and antithrombotic benefits in addition to promoting vasodilation.
Yokoyama, M.; Origasa, H. et. al. "Effects of eicosapentaenoic acid in major coronary events in hypercholesterolemic patients (JELIS - Japan Eicosapentaenoic acid (EPA) Lipid Intervention Study)." Lancet, 369:1090-98;March 2007.