New study shows Omega-3s reduce admission to hospital and deaths from heart failure


The first large scale clinical trial assessing the effects of omega-3 fatty acids on risk reduction in cardiac patients has measured significant benefits. The study, dubbed the GISSI-HF Trial (Gruppo Italiano per lo Studio della Soprevvivenza nell’Infarto miocardico) included 6975 patients from 326 cardiology and 31 internal medicine centres in Italy.  All had chronic heart failure classified according to the European Society of Cardiology guidelines. They were randomly assigned to take either a placebo or a 1g ethyl ester fish oil concentrate providing 850-882 mg of combined eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) per day for 3.9 years.

Researchers measured two primary end points: Time to death and Admission to hospital for cardiovascular reasons. They found that mortality rates were reduced by nine percent and hospital admission for cardiovascular reasons was cut by eight percent in the Omega-3 supplement group compared to placebo. Although these improvements were modest, they clearly showed that long-term supplementation with 1 g per day of omega-3 rich fish oil would be expected to provide similar benefits during routine use in the real world (outside the confines of a clinical trial).

Heightened interest in the beneficial effects of the omega-3 long chain polyunsaturated fatty acids (LC-PUFAs), EPA and DHA on cardiovascular health has come partly from epidemiological and population studies showing that higher dietary fish intake is associated with a lower mortality and morbidity risk from cardiovascular disease (CVD). Various studies have also shown that higher long term intake of fish (up to 2-3 servings per week) is associated with lower primary and secondary heart attack rates and death from CVD.2,3,4.

Previous controlled clinical trials have shown that dietary supplementation with fish oil derived omega-3 fatty acids can, reduce the major risk factors associated with CVD including high blood pressure5,6, high blood triglycerides7,excessive blood clotting8,9, prevent irregular heart beat (anti-arrhythmic effects)10, improve plaque stability (prevents fatty, fibrous plaque on the inside of blood vessels from dislodging which can lead to blockages in other locations within the body resulting in stroke)11,and prevent initiation of an inflammatory response within blood vessels which contributes to plaque formation10.

The first clinical trial to demonstrate a protective role of omega-3 LC-PUFAs was the diet and reinfarction trial (DART)12. It included 2033 men who recently had heart attacks.  Half of the participants were asked to increase their intake of fatty fish to twice weekly or alternatively take fish oil capsules for 2 years. Those advised to eat fatty fish or take supplements had a 29% reduction in 2 year all-cause mortality compared with those not so advised. This effect, which was significant, was not altered by adjusting for ten potential interfering factors.  The intake of omega-3 LC-PUFAs was 0.5 – 1 g per day in the fish/fish oil supplement group. Results of this study were later  confirmed in a number of similar subsequent trials including the GISSI-Prevenzione trial involving 11,323 patients taking 850-882 mg/day of omega 3 LC-PUFAs for 3.5 year13. Individuals taking LC-PUFA supplements had a significant reduction in overall cardiovascular deaths and sudden cardiac death dropped by 45 %.  In addition, the Physicians’ Health Study measured a strong inverse relationship between blood levels of omega-3 LC-PUFAs and risk of sudden death among men with no prior cardiovascular disease14. This latest large scale intervention trial has provided conclusive evidence of benefits that can be achieved in patients with a previous history of cardiac arrest.


  1. GISSI-HF Investigators. Effect of n-3 polyunsaturated fatty acids in patients with chronic heart failure (the GISSI-HF trial): a randomized, double-blind, placebo-controlled trial. The Lancet Aug 31, 2008. DOI:10.1016/S0140-6736(08)61239-8.
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  13. Marchioli R et al. Early protection against sudden death by n-3 polyunsaturated fatty acids after myocardial infraction – time course analysis of the results of the Gruppo Italiano per lo Studio della Sopravvivenza nell’Infarto Miocardico (GISSI)-Prevenzione. Circulation. 2002;105:1897-1903.
  14. Albert CM et al. Blood levels of long-chain n-3 fatty acids and the risk of sudden death. N Engl J Med 2002 Apr 11;346(15):1113-8.