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e have all heard that consuming fish is good for us, but some persons simply do not like the taste of fish, while others worry about polluted waters. Regardless of your opinion of fish, it is important to know about omega-3 fatty acids and ensure your diet is properly balanced to include the right mix and right amount of these fats. To whet your appe

Table 1

tite for information on omega-3s, Table 1 lists some of their benefits. Many of these are especially applicable to your elderly patients and residents. Are they getting enough of these essential fatty acids? Review your menus and add some foods high in omega-3s, or consider supplementation, if necessary. Your dietitian can even use a nutrient-analysis program to analyze your facility’s menus to determine their exact omega-3 fatty acid content. Read on to learn more about how these fatty acids affect how you feel and function each day.

Omega-3 Fatty Acids: The Basics

       Dietary fat is comprised of fatty acids, which contain various numbers of carbon molecules and double bonds. These chemical properties give rise to short- or long-chain fatty acids that are saturated (ie, no double bonds) or unsaturated. The unsaturated fatty acids are either monounsaturated (one double bond) or polyunsaturated. The two types of polyunsaturated fatty acids, omega-3 and omega-6, are distinguished by the location of the first double bond from the methyl end of the fatty acid. Omega-3 and omega-6 fatty acids are essential fatty acids; they are not synthesized in vivo and must be obtained from the diet. In general, omega-6 fatty acids (found in vegetable oils, dairy products, meat, and processed foods) are abundant in the diet. Omega-3 fatty acids include plant-derived alpha-linolenic acid and marine-derived eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Epidemiologic, experimental, and studies have shown many health benefits of omega-3 fatty acids. In particular, the omega-3 fatty acids EPA and DHA may confer protective effects against coronary heart disease (CHD). Several mechanisms may be responsible for the cardioprotective effects of EPA and DHA, such as preventing arrhythmias, lowering heart rate and blood pressure, decreasing platelet aggregation, and lowering plasma triglyceride levels. There are also putative beneficial effects of omega-3 fatty acids in inflammatory conditions, such as rheumatoid arthritis, and for mental health. Indeed, high concentrations of DHA are found in the brain and other parts of the central nervous system. Intriguingly, prospective studies have linked both all-cause dementia and Alzheimer’s disease with decreased fish intake and low plasma phospholipid DHA levels.¹

Sources of Omega-3 Fatty Acids

       Food is an important source of omega-3 fatty acids. Certain seed oils (eg, canola and flaxseed) and nuts (eg, walnuts) contain alpha-linolenic acid. Although alpha-linolenic acid can undergo conversion to EPA in the body, rates of this conversion may be low. The most concentrated source of EPA and DHA from food is fatty fish, such as sardines, salmon, and herring (see Figure 1). Studies show that consuming 6 oz per week of these fatty fish may provide important health benefits. More frequent consumption of fish containing lower amounts of EPA and DHA, such as halibut and scallops, may also provide health benefits.

Figure 1

       Importantly, some species of fish (notably shark, king mackerel, swordfish, and tilefish) contain high levels of methyl mercury, dioxins, polychlorinated biphenyls (PCBs), and other environmental contaminants. However, studies in adults (excluding pregnant women) show that the benefits of consuming 1–2 servings of fish per week exceed the potential health risks associated with contaminants, such as methyl mercury and PCBs.² Consumption of commercially prepared fried fish, which typically contain low levels of EPA and DHA, is unlikely to lower cardiovascular risk. Farmed fish can provide similar amounts of EPA and DHA as do wild fish; however, farmed fish are captive and can accumulate pesticides, antibiotics, and other pollutants. Salmon from supermarkets and restaurants is often farmed and labeled as “Atlantic salmon.” This type of salmon can contain elevated levels of pesticides, PCBs, and dioxins. Wild-caught salmon from Alaska (eg, chinook, sockeye) and farmed Arctic char (a member of the salmon family) are considered the best choices for salmon. Although there is a growing selection of foods (eg, eggs and salad dressings) supplemented with EPA and DHA, additional studies are needed to confirm their health benefits.
       If including fatty fish in the diet is not an option, or when sufficient amounts of EPA and DHA are not obtained from diet, then the use of EPA and DHA in capsule form may be considered. Capsule forms of EPA and DHA are available as dietary supplements and as a prescription formulation of omega-3-acid ethyl esters (P-OM3). P-OM3 is a Food and Drug Administration (FDA)-approved lipid-lowering agent to be used in conjunction with diet for the reduction of severe hypertriglyceridemia levels (> 500 mg/dL) in adults.³
       There are important differences between the prescription and dietary-supplement preparations of EPA and DHA. The manufacturing of prescription pharmaceutical products is regulated by the FDA. In contrast, the FDA must prove a dietary supplement is harmful rather than requiring the manufacturer to prove that the supplement is safe. Recent FDA regulations will require dietary supplement manufacturers to comply with regulations to “evaluate the identity, purity, strength, and composition of their dietary supplements” by June of 2008. The United States Pharmacopeia (USP) is a nongovernmental, nonprofit organization with a verification program for dietary supplements. This program assures consumers that a dietary supplement bearing the USP verification mark has accurate ingredient labeling and follows USP-verified good manufacturing practices. The USP verification program does not, however, comprehensively address the safety and efficacy of the product.
       Nonprescription, USP-verified omega-3 fatty acid capsules contain approximately 300 mg of combined EPA and DHA per 1000-mg capsule.⁴ P-OM3 contains a combined total of approximately 840 mg of EPA and DHA per 1000-mg capsule.³ Thus, patients and their caregivers should be aware of both the qualitative and quantitative differences between dietary supplement omega-3 fatty acids and P-OM3.

Omega-3 Fatty Acid Intake Recommendations

       In general, about 250–500 mg/day (or about 1500–2000 mg per week) of EPA and DHA is associated with reduced risk of CHD death and sudden death (sudden loss of pulse of presumed cardiac etiology).² This amount can be met by consuming one 6-oz serving per week of wild salmon, sardines, or other fatty fish, or by more frequent consumption of fish containing lesser amounts of EPA and DHA. The American Heart Association (AHA) advises the consumption of two or more servings of fish per week in addition to foods (eg, flaxseed oil, walnuts) rich in alpha-linolenic acid. In patients with documented cases of CHD, approximately 0.85–1 g of EPA and DHA in capsule form (in consultation with a physician) may be considered as an adjunct to diet. Recent AHA guidelines also state that, as an adjunct to diet, omega-3 fatty acids in capsule form (approximately 0.85–1 g of EPA and DHA) may be considered in women with CHD.⁵ Healthcare professionals should note that the FDA advises that no more than 2 g per day of omega-3 fatty acids be provided by dietary supplements.⁶

Putting It All Together

       Depression, cardiovascular disease, type 2 diabetes, fatigue, dry and itchy skin, brittle hair and nails, inability to concentrate, and joint pain have all been related to an imbalance or lack of essential fatty acids. So the next time you are looking for a snack or cannot decide what to eat, select something high in omega-3 fatty acids. You never know—you might just feel better!