Contrary to previous findings, daily treatment with fish oil may lack benefit on heart health and heart disease-related mortality, a study reports.
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). There is supportive evidence from multiple studies that suggests the intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements lowers triglycerides; reduces the risk of death, heart attack, dangerous abnormal heart rhythms, and strokes in people with known cardiovascular disease; slows the buildup of atherosclerotic plaques ("hardening of the arteries"), and lowers blood pressure slightly. However, high doses may have harmful effects, such as an increased risk of bleeding. Although similar benefits have been proposed for alpha-linolenic acid, the scientific evidence is less compelling, and the beneficial effects may be less pronounced.
Previous studies suggest that omega-3 fatty acids from fish oil may benefit people who have had a previous heart attack or heart failure. In the current trial, researchers evaluated the potential benefit of this therapy in people with multiple heart disease risk factors or other related disease who had not had a previous heart attack.
The research team enrolled 12,513 people who were randomly assigned to receive either 1 gram of omega-3 fatty acids from fish oil or olive oil placebo daily. At first, the team considered the subjects' rate of death, heart attack, and stroke to be the primary end point of the study. However, when the event rate was found to be lower than expected after one year, the researchers designated the primary end point as time to death from heart disease-related causes or hospital admissions for these causes.
A total of 6,244 people received fish oil, while 6,269 received the olive oil placebo. After five years of follow-up, death from heart disease-related causes or hospital admissions for these causes occurred in 1,478 people. Of these people, 733 had received fish oil while 745 received placebo.
The scientists concluded that daily treatment with fish oil may lack benefit on heart disease-related deaths or hospital admissions. More research is needed to better understand and confirm these findings.
In addition to fish oil, numerous other integrative therapies have also been studied for use in heart disease treatment and prevention. Among those supported by strong scientific evidence are beta-glucan, beta-sitosterol, folate, garlic, red yeast rice, and soy.
For more information about fish oil, please visit Natural Standard's Foods, Herbs & Supplements Database.
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