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There are numerous reports of the benefits of omega-3 fatty acid supplementation, including benefits for heart health, cancer, depression, and attention-deficit hyperactivity disorder. However, the most significant evidence of benefit from omega-3 fatty acid is in managing coronary heart disease (CHD), high triglycerides, high blood pressure, rheumatoid arthritis, and prevention of further heart problems in people with heart disease. Omega-3 fatty acids are found in fish oil.
Sudden Cardiac Death & Coronary Heart Disease(CHD)-Death
Omega-3 fatty acids may help regulate the heart’s rhythm and provide protection against ventricular arrhythmias that lead to death. As a result, the primary benefits of daily fish oil (1 g/day) intake are related to reducing sudden cardiac death events and coronary heart disease-related death (including heart attack) in populations with and without CHD. In patients at high risk for ischemia related abnormal heart rhythms, the reduction in risk off sudden cardiac death is seen within 3 months of treatment.
A recent study (The large Risk and Prevention Study) of 13,513 patients with multiple cardiovascular risk factors or known vascular disease found no additional reduction in risk of death from cardiovascular causes or admission to the hospital for cardiovascular causes with use of omega-3 fatty acids (11.7% with omega-3 fatty acids vs. 11.9% with placebo). While there is still substantial evidence supporting the use of omega-3 fatty acids, additional large trials with long-term follow-up are needed to clarify whether omega-3 fatty acid supplementation might have different effects on cardiac death depending on whether patients are also receiving aggressive treatment for primary or secondary prevention of CHD.
Coronary Heart Disease & Atherosclerosis
Several studies, including a three-year study in 229 women found that omega-3 fatty acid intake was associated with less progression of coronary stenoses and fewer new lesions, suggesting that fish oil consumption may modestly reduce chronic progression of atherosclerosis.
There is strong scientific evidence that omega-3 fatty acids significantly reduce triglyceride levels when used at higher doses (>2 g/day). Higher doses have been found to have greater effects, and a dose of four grams daily may lower triglyceride levels by up to 40%, which is similar to other prescription drugs used in management of high triglycerides. There may be additional reduction in triglycerides when used with statin drugs such as simvastatin and atorvastatin. Omega-3 fatty acids also modestly increase HDL (good fat) and LDL (bad fat) levels.
High Blood Pressure
Many studies report that omega-3 fatty acids may help reduce blood pressure (BP) slightly, while others report no change at all. Effects may depend closely on the dose used, and may be greater in people who have high blood pressure.
In an analysis of 36 trials, fish oil supplementation (3.7 g/day, duration 8 weeks) among adults older than age 45 lowered systolic blood pressure (BP) by 3.5 mmHg and diastolic BP by 2.4 mmHg. In younger healthy adults (younger than age 45), the BP-lowering effects were less pronounced.
Secondary Prevention of Heart Disease
Fish oil has been studied for use in protecting people with previous heart problems from further complications such as heart attack or sudden death. Many studies report the reduction in risk of nonfatal and fatal heart attack, sudden death, and death in people with a history of heart attack when omega-3 fatty acids are used for at least 3 months.
There is also evidence of a lower risk of heart failure with omega-3 fatty acid intake. In one large trial of 7046 patients with chronic heart failure, fewer patients treated with 1 gram daily omega-3 FA died (27% vs. 29% in placebo), and there were significant improvements in left ventricular ejection fraction.
Other Reported Benefits
While there are numerous reports of the benefits of omega-3 fatty acids for various diseases such as dementia, depression, asthma, stroke, cancer. The data supporting these claims are conflicting and limited.
Anti-inflammatory effects of fish oil have also been suggested because omega-3 fatty acids [eicosapentaenoic acid (EPA) and docosahexanenoic acid (DHA)] are precursors to specific inflammatory mediators. However, production and breakdown of these inflammatory metabolites is very complicated, and the effect of EPA and DHA levels is difficult to assess.
Omega-3 fatty acids may affect the immune system and fats in the blood in people with rheumatoid arthritis, which may relate to the improvements in morning stiffness and joint tenderness observed in several studies. Benefits may increase with use of anti-inflammatory medications such as ibuprofen or aspirin. However, effects beyond three months of treatment are unclear, and more research is needed before a firm conclusion may be made about the benefits of omega-3 fatty acids in rheumatoid arthritis patients.
DHA is a necessary structural component of the brain and eye, so omega-3 FA intake in pregnancy during the prenatal and early postnatal periods appears to have modest beneficial effects on neurodevelopment and cognitive outcome of the offspring.
Omega-3 fatty acid supplementation through fish oils have successfully reduced risk of sudden cardiac death and coronary heart disease-related death in people with or without heart disease. It has also successfully decreased triglyceride levels, even in patients already on other prescription products for cholesterol management.
Maintaining a balanced diet of nutrients as well as healthy fats is critical for overall health management. Omega-3 fatty acids are lacking in the traditional American diet, so supplementation is often necessary. As more data is collected on the role of omega-3 fatty acids in combating other diseases, there may be a greater trend towards increased dietary fish intake or fish oil supplementation.
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Kris-Etherton PM, Harris WS, Appel LJ. AHA Scientific Statement: Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease. Circulation. 2002; 106:2747. Accessed February 5, 2014.
The Risk and Prevention Study Collaborative Group. n-3 fatty acids in patients with multiple cardiovascular risk factors. N Engl J Med. 2013;368(19):1800-1808.
Mozaffarian D. Fish oil and marine omega-3 fatty acids. In: UpToDate, Fletcher RH (Ed), UpToDate, Waltham, MA. Accessed on February 5, 2014.
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