Research Glimpse: In 2002, the American Heart Association (AHA) published a scientific statement (Circulation, 106: 2747-2757 (2002)) with the recommendation that patients with documented coronary heart disease (CHD) consume close to 1 gram (1000 mgs) per day of omega-3 polyunsaturated fatty acids (PUFA) as EPA plus DHA from oily fish or via supplementation as an option in consultation with a physician. The present 2017 update has reviewed large randomized clinical trials (RCTs) of such omega-3 fatty acid supplementation in relation to major clinical cardiovascular disease (CVD) outcomes. The advisory has now provided recommendations for both clinicians and patients.
Conclusions: ‘Taken together, the cumulative findings from RCTs suggest that the omega-3 PUFA supplements may reduce CHD death, possibly through a reduction in ischemia-induced SCD (sudden cardiac death), among patients with prior CHD…’. ‘…the majority of co-authors concluded that treatment with omega-3 PUFA supplements is reasonable for the secondary prevention of CHD death…’. ‘Although based on a single, large RCT, treatment with omega-3 PUFA supplements is reasonable among patients with heart failure with reduced ejection fraction’.
The report based on a meta-analysis of 20 studies calculated the expected reduction in CHD death and SCD (sudden cardiac death) to be in the order of 10% overall. Furthermore, they note that even such a modest benefit justifies the use of a relatively safe therapy such as omega-3 PUFA. In this regard, it is noted that the daily supplemental dose of omega-3 PUFA (EPA/DHA) in the RCTs as reviewed ranged from 0.5 gm (500 mgs) to 1.8 gm (1800 mgs). The trial on the secondary prevention of outcomes in patients with heart failure as referred to in this report employed a daily dose of supplemental EPA/DHA amounting to 0.84 gm (840 mgs) and a reduction in total mortality of 9%.
NFH notes that the daily doses of supplemental EPA/DHA (omega-3 PUFA) as used in the studies (RCTs) as reviewed by the AHA committee are much higher than typical dietary intakes from fish/seafood due to their infrequent intakes. Such ‘background’ intakes from dietary sources in North America, where one serving of fish/seafood is consumed every 7-10 days, contributes only approx. 100-150 mgs EPA/DHA daily on average. There are extensive ongoing clinical trials which will be employing considerably higher dosages of omega-3 PUFA than have typically been used in the past. The REDUCE-IT trial is designed to determine if 4 gm (4000 mgs) daily of EPA will reduce ischemic cardiac events in patients at increased CVD risk who are already being treated with statins (for blood cholesterol-lowering). The EVAPORATE trial will employ statin-treated patients with elevated blood triglyceride levels (200-400 mgs/100ml) to determine if 4 gm (4000 mgs) daily of EPA can retard the progression atherosclerotic plaque.
Reference: Siscovick, D. S. et al. (on behalf of the Am. Heart Assoc.) Circulation, 2017 Apr. 11; 135(15): e867.