Many people take fish oil supplements because they contain omega-3 fatty acids. Fish oil supplements are clearly proven effective in lowering blood triglyceride levels. And some studies have suggested that omega-3s may prevent sudden death from disturbances in heart rhythm, or arrhythmia. But don’t run to your nearest health food store or grocery store to purchase fish oil supplements just yet.
As with most dietary supplements, the studies supporting some of the claims for fish oil are inconclusive. A 2002 review of many fish oil studies concluded that these supplements did protect against sudden cardiac deaths and cardiovascular events. But a more recent analysis of 48 trials – comparing 37,000 people who had taken either fish oil supplements or a placebo for six months to several years – casts doubt on those results.
Among the people taking fish oil supplements (some but not all of whom had heart disease or its risk factors), there was no significant reduction in the risk of death or of cardiovascular events like heart attacks or strokes. And even though there was no increase in the risk of cancer among the participants, the authors could not vouch for the safety of taking the supplements, which may be contaminated with mercury.
So we still have no conclusive proof for the protective effects of fish oil supplements against sudden death. Although taking these supplements may be a waste of money for most healthy people without risk factors or evidence of arrhythmia, there is still the chance that fish oil supplements can protect certain individuals, especially people with some heart rhythm abnormalities. However, other studies have shown no benefit from fish oil supplements in people who have an implanted defibrillator because of their risk of sudden cardiac death.
