From the Guidelines
Fish oil supplements are not recommended as a primary prevention strategy for cardiovascular health in everyone, but may be beneficial for individuals with high triglyceride levels or established cardiovascular disease, under the guidance of a physician. The most recent and highest quality study, published in 2021 1, suggests that prescription-strength fish oil, such as Vascepa (icosapent ethyl) at 2 grams twice daily or Lovaza (omega-3-acid ethyl esters) at 4 grams daily, may be appropriate for patients with very high triglycerides (>500 mg/dL). These supplements contain omega-3 fatty acids (primarily EPA and DHA) that can help reduce triglyceride levels by 20-30% when taken at doses of 2-4 grams daily.
Some key points to consider when using fish oil supplements for cardiovascular health include:
- They work by decreasing the liver's production of VLDL and triglycerides while potentially offering anti-inflammatory effects that may benefit the cardiovascular system.
- Their impact on reducing heart attack or stroke risk is less clear, with mixed results from clinical trials.
- For general heart health, consuming fatty fish like salmon or mackerel twice weekly is preferable to supplements.
- People taking blood thinners should consult their doctor before starting fish oil supplements due to potential increased bleeding risk.
- Common side effects include fishy aftertaste, bad breath, heartburn, and nausea, which can be minimized by taking supplements with meals or using enteric-coated products.
It's also important to note that nonprescription fish oil products are not interchangeable with prescription omega-3 products, and their content and quality can vary significantly 1. The American Heart Association recommends that all adults eat fish (particularly fatty fish) at least two times a week, and that patients with documented coronary heart disease consume 1 g of EPA+DHA per day, preferably from oily fish, although EPA+DHA supplements could be considered in consultation with their physician 1.
From the Research
Role of Fish Oil in Cardiovascular Health
- Fish oil supplements, which contain omega-3 polyunsaturated fatty acids, have been studied for their potential role in preventing clinical cardiovascular disease 2.
- The American Heart Association recommends consuming two servings of fish per week for persons with no history of coronary heart disease and at least one serving of fish daily for those with known coronary heart disease, with approximately 1 g/day of eicosapentaenoic acid plus docosahexaenoic acid recommended for cardio protection 3.
- Omega-3 fatty acids have been shown to significantly reduce the risk for sudden death caused by cardiac arrhythmias and all-cause mortality in patients with known coronary heart disease 3.
Effects of Omega-3 Fatty Acids on Cardiovascular Disease Risk Factors
- Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to have independent effects on lipid and apolipoprotein levels, as well as on inflammatory biomarkers of cardiovascular disease risk 4.
- A randomized clinical trial found that DHA decreased postprandial triglyceride concentrations, but raised low-density lipoprotein cholesterol, while high-dose EPA had beneficial effects on cardiovascular disease risk reduction by lowering lipoprotein-associated phospholipase A2 concentrations without adversely affecting low-density lipoprotein cholesterol 4.
Dietary Recommendations for Cardiovascular Disease Prevention
- A heart-healthy diet should be high in fruits, whole grains, legumes, and nonstarchy vegetables, and low in trans-fats, saturated fats, sodium, red meat, refined carbohydrates, and sugar-sweetened beverages 5.
- The Dietary Approaches to Stop Hypertension, Mediterranean, and vegetarian diets have the most evidence for cardiovascular disease prevention, and clinicians should understand the barriers that patients may face in terms of access to healthy dietary choices 5.
Controversies and Future Directions
- Recent clinical trials have reported contradictory results on the cardiovascular effects of omega-3 fatty acids, with some studies showing benefits and others showing no effect or even harm 6.
- The differences in results may be due to various factors, including the type and dose of omega-3 fatty acids used, the comparator used, and the underlying severity of cardiovascular disease risk or use of statins 6.