Author: Yvette C. Terrie, BSPharm, RPh
Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.
A variety of dietary supplements containing essential fatty acids are on the market today to promote cardiovascular health. These supplements contain omega-3 fatty acids alone or in conjunction with omega-6 and omega-9 fatty acids.
Sources of omega-3 fatty acids include fattier fish, such as tuna, mackerel, and salmon. Research has demonstrated that these essential fatty acids are associated with certain health benefits when consumed in the recommended amounts, especially when used to replace saturated fats or trans fats in the diet.1
These fatty acids play a crucial role in heart and brain function and in normal growth and development.1,2
Omega-3 and omega-6 fatty acids cannot be synthesized in the body and must therefore be obtained from the diet or dietary supplements.2
For cardiovascular protection, the American Heart Association (AHA) recommends the consumption of omega-3 fatty acids from fish and plant sources at least twice weekly (Table).1
Fatty fish contain 2 kinds of omega-3 fatty acids—eicosapentaenoic acid and docosahexaenoic acid.2
Tofu and other forms of soybean, walnut, flaxseed, and canola oils contain alpha-linolenic acid (ALA), which can be converted to omega-3 fatty acids in the body.3
The role of omega-3 fatty acids in cardiovascular disease (CVD) is still being studied; however, research has shown that omega-3 fatty acids can reduce the risk of arrhythmia, lower triglyceride levels, and decrease the growth rate of atherosclerotic plaque.4
Furthermore, results from both epidemiologic and clinical trials have demonstrated that omega-3 fatty acids can decrease the incidence of CVD, and large-scale epidemiologic studies suggest that individuals at risk for developing coronary heart disease may actually benefit from consuming omega-3 fatty acids from plants and marine sources.4,5
The consumption of omega-3 fatty acids through dietary means is the ideal option; however, patients may choose to use omega-3 dietary supplements due to their convenience or an inability to consume enough omega-3 fatty acids through diet alone.
Omega-6 and Heart Health
A science advisory from the AHA published earlier this year concluded that omega-6 fatty acids, which are found in some vegetable oils, nuts, and seeds, are a beneficial part of a heart-healthy eating plan.1
Highlights from the advisory include1
• Individuals should consume at least 5% to 10% of their total daily calories from omega-6 fatty acids.
• Individuals should replace saturated fats with polyunsaturated fats, which are natural sources of omega-6.
• Omega-6 fatty acids may help reduce CVD risk.
• Higher intakes of omega-6 may improve insulin resistance, reduce diabetes risk, and lower blood pressure.
Omega-6 fatty acids found in supplements are linoleic acid (LA) and gamma linolenic acid (GLA), such as evening primrose oil (Oenothera biennis) and blackcurrant (Ribes nigrum) oils. Spirulina (often called blue-green algae) also contains GLA.6-8
A variety of omega-3 fatty acid supplements are available in various dosage forms and strengths, as singleentity products or in combination with omega-6 (LA or GLA) and omega-9 (oleic acid) fatty acids. Common adverse effects associated with the use of these supplements include acid reflux, heartburn, indigestion, nausea, diarrhea, and increased burping.4-6
Gastrointestinal side effects can be minimized if supplements are taken with meals, if doses are started low and gradually increased, or if enteric-coated products are used.4,6
Patients with allergy or hypersensitivity to any of the ingredients of these products should avoid their use.
Considerations for Use
The use of these supplements has been associated with various drug–drug interactions, including antithrombotic therapy (ie, warfarin, clopidogrel, aspirin), and patients should be warned about the potential of an increased risk of bleeding when these medications are taken with omega-3 supplements.4-6
These supplements also may interact with nonsteroidal anti-inflammatory drugs and some herbal supplements.4,5
Supplements containing GLA or other omega-6 supplements should not be used if the patient is being treated for a seizure disorder due to reports of seizures associated with their use.7
These supplements should not be used during pregnancy because of the potential of harm to the fetus or possibility of inducing preterm labor.6
Other interactions associated with omega-6 supplements have been reported with monoamine oxidase inhibitors and selective serotonin reuptake inhibitors, as well as antineoplastic agents, antiobesity agents, antiviral agents, and central nervous system stimulants.7
The use of fish oil supplements may slightly lower blood glucose, and thus, these supplements should be used with caution by patients with diabetes.4,5
Patients who take >3 g of omega-3 fatty acids from capsules should do so only under a physician’s care, because high intakes could cause excessive bleeding in some people or exacerbate heart rhythm in individuals with arrhythmia. 1,5,6
Patients who plan to undergo surgery requiring anesthesia should be advised to stop taking supplements containing evening primrose oil at least 2 weeks before the surgery because of the possibility of seizure.7
Prolonged use of fish oil supplements may cause vitamin E deficiency; therefore, vitamin E is often added to many commercial fish oil products.4
Patients should be reminded that the regular use of vitamin E–enriched products may lead to elevated levels of this fatsoluble vitamin, so patients should be monitored.4
Patients should be encouraged to discuss the use of these supplements with their primary health care provider to ascertain appropriateness prior to use, especially if they are currently on any prescription medications or have preexisting medical conditions, including women who are pregnant or breastfeeding. Patients should be advised to take these supplements as directed and contact their primary health care provider about any concerns.
When assisting patients in the selection of these supplements, pharmacists can use the opportunity to remind patients to adhere to a balanced diet low in saturated fat and cholesterol, as well as the importance of nonpharmacologic measures that may decrease cardiovascular risks, such as weight loss, smoking cessation, limiting alcohol intake, and establishing an exercise routine, if appropriate. ■
1. Harris JW, Mozaffarian D, Rimm E, et al. Omega-6 fatty acids and risk for cardiovascular disease: a science advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention. Circulation. 2009;119(6):902-907.
2. Kandasamy N, Joseph F, Goenka N. The Role of Omega-3 Fatty Acids in Cardiovascular Disease, Hypertriglyceridaemia and Diabetes Mellitus. Medscape Web site. www.medscape.com/viewarticle/576628. Accessed September 28, 2009.
3. American Heart Association Clarifies the Role Omega-6 Fatty Acids. American Heart Association Web site. www.americanheart.org/presenter.jhtml?identifier=3063253.Accessed September 29, 2009.
4. Fish and Omega 3 Fatty Acids. American Heart Association Web site. www.americanheart.org/presenter.jhtml?identifier=4632. Accessed September 29,2009
5. Omega 3 fatty acids, fish Oil, alpha linolenic acid. Medline Plus Web site. www.nlm.nih.gov/medlineplus/druginfo/natural/patient-fishoil.html. Accessed September 28, 2009.
6. McQueen C., Orr K. Natural Products. In: Berardi R, Newton G, McDermott JH, et al, eds. Handbook of Nonprescription Drugs. 16th ed. Washington, DC: American Pharmacists Association; 2009:975