Dietary sources of omega-3 fatty acids include fish oil and certain plant and nut oils. Fish oil contains both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), while some nuts (such as English walnuts) and vegetable oils (such as canola, soybean, flaxseed, linseed and olive oils) contain alpha-linolenic acid (ALA).
Several well-conducted randomized controlled trials have reported that in people with a history of heart attack, regular consumption of oily fish or fish oil or omega-3 supplements reduces the risk of nonfatal heart attack, fatal heart attack, sudden death and all-cause mortality (death due to any cause). Most patients in these studies were also using conventional heart drugs, suggesting that the benefits of fish oils may add to the effects of other therapies.
Several large studies of populations have also examined the effects of omega-3 fatty acid intake on stroke risk. Some studies suggest benefits, while others do not. Effects are likely on stroke risk, and very large intakes of omega-3 fatty acids may actually increase the risk of hemorrhagic (bleeding) stroke. At this time, it is unclear if there are benefits in people with or without a history of stroke, or if effects of fish oil are comparable to other treatment strategies.
In a new study, researchers conducted a comprehensive literature search for well-designed clinical trials evaluating the effects of omega-3 fatty acids on death due to heart disease, sudden death, heart attack, stroke and death from any cause. Twenty studies assessing 60,680 individuals were ultimately identified for inclusion.
From the 20 studies, 7,044 deaths from any cause, 3,993 deaths due to heart disease, 1,150 sudden deaths, 1,837 heart attacks and 1,490 strokes were identified.
Through data analyses, the researchers found that a significant association between omega-3 fatty acid intake and risk for death from any cause, death due to heart disease, sudden death, heart attack or stroke, was lacking.
The authors concluded that omega-3 fatty acid supplementation may not reduce the risk for heart disease or stoke. However, additional research is necessary to further evaluate these findings.
For more information about integrative therapies for heart disease prevention, please visit Natural Standard's Comparative Effectiveness Database.
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