Omega-3 fatty acids in fish reduce risk of sudden cardiac death
More than 50% of people who die suddenly from cardiac causes have no history of heart disease. Because sudden cardiac death is their first sign of heart disease, it seemed that there was no opportunity to prevent these deaths—until now. A great deal of research suggests that the long chain omega-3 fatty acids found in fish can protect the heart. And a recent study published in The New England Journal of Medicine found that among men without cardiovascular disease, those with more omega-3 fatty acids in their blood were less likely to die of sudden cardiac death.
About the study
Researchers from Boston’s Brigham and Women’s Hospital and Harvard School of Public Health studied 278 men in the Physicians Health Study—a large, ongoing study of male physicians. When the study began in 1982, all the men were between the ages of 40 and 84 and had no history of heart attack, stroke, transient ischemic attacks, or cancer.
A blood sample was collected from each man at the start of the study. Each year throughout the study, the men also completed questionnaires about their health status, dietary habits, and risk factors for cardiovascular disease.
In 1999, after 17 years of follow-up, the researchers reviewed the medical records of 94 men who had died suddenly of cardiac causes (cases). They thawed the original blood samples provided by these men and measured the long-chain omega-3 fatty acids in the blood. They also thawed and tested the original blood samples of 184 men in the study who were still living and free of cardiovascular disease in 1999 (controls). Controls were matched to cases in terms of both age and smoking status.
Finally, the researchers compared blood levels of long-chain omega-3 fatty acids in the cases and in the controls. They also compared the men’s reported fish intake on the first annual dietary questionnaire with their blood levels of long-chain omega-3 fatty acids.
Compared to men with the lowest blood levels of long-chain omega-3 fatty acids, those with the highest levels were 81% less likely to die of sudden cardiac death. And, the men’s reported fish intake correlated to their blood levels of omega-3 fatty acids, indicating that fish intake was likely the source of the omega-3 fatty acids in their blood.
In calculating these statistics, the researchers accounted for other risk factors for cardiac death including: age, smoking, body mass index (BMI), diabetes, high blood pressure, high cholesterol, alcohol intake, exercise, and family history of premature heart attack.
There are limitations to this study however. Because this study included only men, research in women is needed to determine whether women reap the same benefits from fish oil. In addition, the blood levels of omega-3 fatty acids were measured only once from a sample taken at the start of the study. These levels may not reflect long-term blood levels of omega-3. Finally, it’s possible that dietary, genetic, or lifestyle factors not accounted for in this study significantly influence the risk of sudden cardiac death.
How does this affect you?
Should you start eating more fish or taking omega-3 fatty acid supplements? Absolutely. This study adds to a growing body of evidence that consuming omega-3 fatty acids in fish and supplements may reduce your risk of heart disease, stroke, heart attack, and now, sudden cardiac death. The main lesson from this study is that fish and omega-3 fatty acid supplements may reduce the risk of sudden cardiac death in men who don’t even have cardiovascular disease.
The American Heart Association recommends eating at least two servings of fish each week. In addition to possibly preventing heart disease and stroke, seafood is an excellent source of protein and a tasty meat replacement. So even if you’re not likely to eat fish as a main course, you might consider the following:
- Fish chowders
- Tuna fish salad
- Crab cakes
- Grilled fish sandwich
- Seafood pasta salad
Albert CM, et al. Blood levels of long-chain n-3 fatty acids and the risk of sudden death. New England Journal of Medicine. April 11, 2002;346(15):1113-1118.
Rosenberg IH. Fish— Food to Calm the Heart. New England Journal of Medicine. April 11, 2002;346(15):1102-1103.
Last reviewed Apr 17, 2002 by ]]>Richard Glickman-Simon, MD]]>
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