- Resource Centers
Whether obtained through diet or supplements, omega-3 fatty acids provide many benefits to cardiovascular health.
According to the results of a 2007 survey conducted by the National Center for Health Statistics and the National Center for Complementary and Alternative Medicine, omega-3 supplements were the most commonly used nonvitamin/nonmineral natural products among adults and the second most common among children.1 Omega-3 fatty acids are a class of polyunsaturated fatty acids that are essential to several functions in the body, including relaxation and contraction of muscles, digestion, blood clotting, cell division, and movement of calcium and other substances in and out of cells.1
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are 2 of the most important omega-3 fatty acids found in fish oil.2 Another omega-3 fatty acid, alpha-linolenic acid (ALA), is found in plant sources.2 It is preferred that individuals consume omega-3 fatty acids through dietary means; however, many patients may elect to take omega-3 dietary supplements due to their convenience, or because they are unable to ingest enough omega-3 fatty acids through diet alone.
Benefits of Omega-3
Epidemiologic studies conducted more than 3 decades ago reported relatively low mortality related to cardiovascular disease among individuals in Eskimo populations who consumed a large amount of fish. Since these findings were published, several other observational and clinical trials have studied the effects of fish oil and omega-3 fatty acids on a number of conditions,1 with evidence most promising for improving cardiovascular disease risk factors.1
In addition, there is strong scientific evidence suggesting that intake of 800 to 1500 mg per day of EPA/DHA reduces risk of myocardial infarction and death due to arrhythmia in patients with preexisting coronary artery disease who are taking conventional medications.3 One study reported that increasing the intake of DHA and EPA by dietary consumption or by taking fish oil supplements resulted in lower triglyceride levels, slightly decreased blood pressure, slowing down of the progression of atherosclerosis, and a decreased risk of heart attack, stroke, and death among those with cardiovascular disease.1
The American Heart Association (AHA) recommends that all individuals consume omega-3 fatty acids from fish and plant sources at least twice a week because of their role in cardiovascular protection. It is also recommended that those with coronary heart disease (CHD) eat a variety of fish—preferably oily fish such as salmon, tuna, mackerel, herring, and trout—at least twice a week.4 Individuals with CHD are also advised to consume an approximately 1 g of EPA and DHA daily, preferably from oily fish, although EPA DHA supplements could be considered after consulting with a primary health care provider.5 The AHA also states that individuals who have elevated triglycerides may need as much as 2 to 4 g of EPA and DHA per day in supplement form, but only under the care and monitoring of a physician.5
Omega-3 fatty acid supplements are available in different dosage forms and strengths, and as single-entity products or in combination with other dietary supplements (Table). One of the newest products on the market is Pfizer’s ProNutrients Omega-3 minigel capsules, which contain EPA and DHA. Another new product is Astamega 3 Cardio Support (Patent Health LLC), which contains krill oil.
Pharmacists are in a pivotal position to assist individuals in the proper selection of and use of omega-3 fatty acid dietary supplements.
Prior to using these supplements, patients should be encouraged to speak with their primary health care provider to determine whether it is appropriate. This is especially important for patients currently taking prescription or nonprescription medications, or those with pre-existing medical conditions, including women who are pregnant or breastfeeding. Patients should be advised to take these supplements only as directed and to contact their primary health care provider about any concerns. Patients with allergy or hypersensitivity to any of these products should not use them.
Common adverse effects associated with omega-3 supplements include acid reflux/ heartburn, nausea, diarrhea, and increased incidence of burping.6,7 Gastrointestinal side effects can be minimized if fish oil supplements are taken with meals and if doses start low and gradually increase.6-8
Some medications may interact with omega-3 supplements, including aspirin, anticoagulants, antiplatelet agents, and some herbal supplements.6-8 The use of fish oil supplements has been associated with a slight increase in fasting blood glucose levels in some diabetic patients.6-8 These patients should be advised to discuss this issue with their physician.6,7
Furthermore, pharmacists should remind patients who take more than 3 g of omega-3 fatty acids from capsules to do so only under a physician’s care, as high intake may potentially cause excessive bleeding in some patients, or may worsen arrthymias.5,6 Patients should be reminded that prolonged use of fish oil supplements may cause vitamin E deficiency, which explains why vitamin E is added to many commercial fish oil products.6,7 Regular use of vitamin E–enriched products may lead to elevated levels of this fat-soluble vitamin; therefore, it is important that patients are monitored accordingly.6-8
Studies have shown that routine use of omega-3 fatty acids can significantly decrease the risk for sudden death caused by cardiac arrhythmias and for all-cause mortality in patients with known coronary heart disease. Research is continually being conducted to learn more about the value of these fatty acids in other diseases as well.7 During counseling, pharmacists should encourage and remind patients to adhere to a balanced diet low in saturated fat and cholesterol, and should suggest other nonpharmacologic measures that may decrease modifiable cardiovascular risk factors, such as weight loss, smoking cessation, limiting alcohol intake, and establishing an exercise routine, if appropriate.
For more information on the effects of omega-3 fatty acids on cardiovascular disease, please visit the Agency for Healthcare Research Web site at www.ahrq.gov/clinic/epcsums/o3cardrisksum.htm. PT
Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.