Fish Oil Supplements The use offish oil supplements to reduce the risk of heart disease remains controversial. by Kathryn K. Bucci, PharmD

Examples of trade names: MaxEPA, Sea-On1ega 50 Softgels, Marine Lipid Concentrate Softgels Dosage forms: capsules Fish oil products are classified as food supplements rather than nonprescription drugs by the Food and Drug Administration and are con1monly found in community pharmacies. Although several products have recently been discontinued, they continue to be of interest to a significant segn1ent of the population. The pharmacist will find this information useful in advising patients about fish oil supplementation.

contain omega-3 fatty acids.8 Thus, dietalY sources of cold water fish contain the largest alnounts of EPA and DHA3 (Table 1). Several mechanisms may cause omega-3 fatty acids, from dietalY fish or fish oil, to be beneficial in reducing CHD risk. One mechanism involves a decrease in plasn1a lipids by reducing the hepatic synthesis of fatty acids and very-lowdensity lipoproteins, increasing the use of lipoproteins, and fecal steroid elin1ination. 7,9 Another proposed n1echanism involves prostaglandins and their related effects on platelets. 9 EPA and DHA decrease the synthesis of thromboxane, a vasoconstrictor that pron10tes platelet aggregation. 2,3

Introduction Many patients are eager to learn more about strategies to prevent coronary heart disease (CHD), a leading cause of death in the United states. The interest in fish oil to prevent CHD stems from epidemiologic observations that Greenland Eskin10s who eat large alnounts of fish rarely die fron1 cardiovascular disease. 1-4 Because many patients have difficulty with dietary changes, the use of fish oil products as a food supplement Inay be a reasonable alternative. 1 However, the exact role of fish oil remains to be defined.5 This monograph reviews the controversy surrounding use of fish oil products to reduce the risk of CHD and the role of the pharn1acist in counseling patients about the safe use of these products.

Actions Fish oils are polyunsaturated fats found in fish and are an abundant source of omega-3 fatty acids. 6,7 The two predominant omega-3 fatty acids found in fish oil are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).6 These fatty acids are considered essential because they cannot be synthesized by humans and must be ingested in the diet. 8 The common misconception is that fish themselves produce these fats .7 Omega-3 fatty acids are derived from marine phytoplankton and accumulate in fish as they consume these sea plants. 7,8 The colder the surroundings of the phytoplankton, the greater likelihood their membranes will AMERICAN PHARMACY

Clinical Effects The clinical effects of omega-3 fatty acids include: • A decrease in serum triglycerides. A dosage of 4 g to 6 g daily of on1ega-3 fatty acids can be expected to lower elevated triglycerides by 30% to 40%.6 Although this effect is seen within two weeks, some question the ability of fish oil to maintain this effect. 6,l o • A reduction in serum cholesterol. There are conflicting reports of the effect of fish oil supplelnents on lipoproteins associated with atherosclerosis Clow-density lipoproteins- LDL-and high-density lipoproteins- HDL).l1 The cholesterol lowering effect of omega-3 fatty acids may be seen at dosages between 5 g and 20 g daily. 2 These effects may be noted within two weeks of supplementation and disappear two weeks after discontinuation. 1 However, the most recent statelnent of the National Cholesterol Education Program does not recommend fish oil supplen1entation, but rather recomn1ends the consumption of fish as a substitute for meats, which are richer in saturated fats. 1,12 In addition, son1e available products contain cholesterol and saturated fat, which Inay increase LDL cholesterol. ll • A p rolongation of bleeding time. 9 Decreases in platelet reactivity may result in longer bleeding tin1es, particularly in patients concurrently taking aspirin or anticoagulants (e.g. , warfarin).7,8 • A decrease in blood p ressure. 2 • An effect on the development and management of June 1992/ 504 Vol. NS32, No.6

autoimmune and inflammatory conditions, such as rheumatoid arthritis and psoriasis. 2,11 Omega-3 fatty acids may alleviate some subjective complaints of arthritis by interfering with mediators of inflamination, such as prostaglandins and leukotrienes. 13 • Prevention of early restenosis after coronalY angioplasty when cOlnbined with dipyridamole and aspirin in high-risk n1en. 8,11

Indication Based on their effect on platelets and lipids, 0lnega-3 fatty acids may be used as a nondrug dietary supplement (as a part of a total dietary plan) for patients at early risk of CHD;11,14 but data . showing effectiveness are lacking. Other reasonable steps such as regular exercise, sinoking cessation, and weight control should be followed. 14

Side Effects and Adverse Reactions Diarrhea has occurred in patients who have exceeded the manufacturer-recoinmended dosages (4 to 6 capsules daily). 3,9 Nausea and a fishy taste are often encountered. 8 Increased bleeding time and inhibition of platelet aggregation could cause bleeding problems in some patients, particularly those taking anticoagulants or aspirin. 8 Platelet counts Inay decrease as much as 35%; it may take four to six weeks after dietary suppieinents are discontinued for platelet counts to return to normal. 8 Patients with uncontrolled hypeitension who are at risk for hemorrhagic stroke should also be advised not to take fish oil until their blood pressure is controlled. 6 Some fish oils (e.g. , cod liver oil) Inay also contain cholesterol and, in large doses, potentially toxic amounts of vitainins A and D. 2,3,8 One teaspoon of cod liver oil contains 100% of the recommended dietary allowance (RDA) of vitamins A and D. 8 Vitamin E is added to most commercial fish oil products as an antioxidant to stop the oil fro In becoming rancid and to prevent a theoretical (never reported) concern that fish oil consumption n1ay result in a vitamin E deficiency.7,8 However, some of these produ

Fish oil supplements.

Fish Oil Supplements The use offish oil supplements to reduce the risk of heart disease remains controversial. by Kathryn K. Bucci, PharmD Examples o...
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