Page 938 - Cardiac Nursing

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914 PA R T V / Health Promotion and Disease Prevention
Nutraceuticals and Other CAM daily, significantly greater than the average fish oil (EPA, docosa-
Dietary Approaches to hexaenoic acid) intake in Western countries ( 250 mg/day, less
Cardiovascular Health than one serving of fatty fish per week). Fish oil was found to re-
duce systolic blood pressure by 2.1 mm Hg and diastolic blood
Nutraceuticals derive their name from “nutrition” plus “pharma- pressure by 1.6 mm Hg. Blood pressure reduction tended to be
ceutical.” The term refers to food extracts claimed to have thera- greater in persons older than 45 years and in those with hyper-
peutic effect. Among the nutraceuticals used in cardiac conditions tension (BP 140/90 mm Hg). The antihypertensive effect did
are omega-3 fatty acids, red yeast rice, coenzyme Q10, garlic, not appear to be dose dependent. The effect was noted in one
niacin, and plant sterols. Dietary approaches are important ad- trial at a relatively low dose of 180 mg/day. It has been suggested
juncts to the treatment of cardiovascular diseases, including hy- that fish oil may influence the arteries, reducing blood pressure
pertension, although some of these approaches are associated with by evoking vasodilation. Older meta-analyses from the 1990s
risk. show a dose–response reduction of blood pressure of 3.4/2.0
mmHg with 5.6 grams of fish oil per day, reduction of 5.5/3.5
Omega-3 Fatty Acids mm Hg in trials of 3 g/day, and 2.1/1.6 mm Hg with 3.7 g/day
Omega-3 and omega-6 fatty acids are essential nutrients, not syn- in hypertensive patients. 48 Blood pressure reductions associated
thesized by the human body; thus, they must be obtained with the Dietary Approaches to Stop Hypertension (DASH) diet
through diet or supplements. Omega-3 Fatty acids have anti-in- may in part be attributed to increased fish intake. 47 It is reason-
flammatory, antiarrhythmic, and antithrombotic properties, dif- able to recommend several servings of fatty fish per week for the
ferent from omega-6 fatty acids, which are proinflammatory. treatment of hypertension. A fish oil supplement may be an ade-
There are three types of omega-3 fatty acids: eicosapentaenoic quate alternative.
acid (EPA), docosahexaenoic acid, and -linolenic acid (ALA). The mechanism underlying the effect of omega-3 fatty acids
Fat-rich fish (e.g., salmon, trout, herring, sardines) are the pri- on blood pressure could be due to the lowering of serum triglyc-
mary source of EPA and docosahexaenoic acid, while ALA gen- eride levels; this in turn causes an increase in LDL particle
erally derives from plant sources such as ground flax seed, flax size. 49–51 Triglyceride concentration is a determinant of LDL con-
seed oil, walnuts, tofu, and soy or from omega-3 enriched eggs. centration; thus, fish oil is expected to lower LDL as well.
Generally, evidence suggests that 0.5 to 1.8 g/day of docosa- Side effects of high levels of fish oil consumption include gas-
hexaenoic acid and EPA either as fatty fish or as supplements sig- trointestinal effects (nausea, bloating, flatulence, eructation). It
nificantly reduces cardiac mortality and morbidity. For ALA, in- has been suggested that fish oil worsens glycemic control in pa-
52
takes of 1.5 to 3.0 g/day are possibly helpful. The American tients with type 2 diabetes mellitus ; however, a meta-analysis
Heart Association recommends at least two weekly servings of found that hemoglobin A1C was not adversely affected with fish
fish (particularly fatty fish) as well as inclusion of ALA food oil consumption. 53 Vitamin E levels decrease with high doses of
sources; fish recommendations should take into account federal omega-3 fatty acids. 54,55 Some fish oil preparations (e.g., cod liver
and state advisories related to environmental pollutants such as oil) contain large amounts of fat-soluble vitamins and could cause
methylmercury and polychlorinated biphenyls. vitamin A or D toxicity. Fish products may be contaminated with
It has long been known that Eskimos and some other popula- toxins such as mercury or pesticides if the fish were caught in con-
tions with high dietary intake of omega-3 fatty acids have lower taminated waters. Mercury is more likely to contaminate fish tis-
heart disease rates. 38 Bucher et al. 39 conducted a meta-analysis of sue than to contaminate fish oil products. Fish oils (as all oils)
11 studies comparing dietary or supplemental omega-3 fatty acids have a high-caloric content and can contribute to weight gain. Be-
to placebo. Subjects in the omega-3 groups had significantly re- cause fish oils could possibly lower blood pressure, there is poten-
duced risk of fatal myocardial infarction (risk ratio 0.7), sudden tial for additive effects in patients treated with antihypertensive
death (risk ratio 0.7), and all-cause mortality (risk ratio 0.8). A drugs. There is also a potential for additive antithrombotic effects.
large study, the Gruppo Italiano per lo Studio della Sopravvivenza Caution is needed for patients with pathological conditions in-
nell’Infarto Miocardico (GISSI) trial, was included in the meta- hibiting clotting and in patients taking aspirin, warfarin, clopido-
analysis. The GISSI trial studied more than 11,000 subjects who grel (Plavix), or herbs such as garlic or ginseng. Fish oil levels were
had experienced a myocardial infarction within the past 3 associated with reduced stroke risk in one study, 56 but another
months. Subjects were randomly assigned to one of four groups: study suggested that very high dietary fish oil consumption in-
fish oil (1 g daily), vitamin E (300 mg daily), both fish oil and vi- creased the risk of hemorrhagic stroke. 57
tamin E, or neither. Subjects receiving fish oil had significantly re-
duced risk of sudden death at 4 months (relative risk 0.47) and at Flaxseed
42 months. 40,41 The fish oil group also had reduced risk of vascu- Whole flaxseed has been linked with lowered serum cholesterol
lar and coronary death beginning at 8 months. Other prospective in subjects without 58,59 and with hypercholesterolemia. 60,61
trials report a similar inverse relationship between fish oil intake Flaxseed products are also used for noncardiac uses, for example,
and coronary events. 42,43 In the U.S. Physicians’ Health Study of to treat constipation, arthritis, cancer, anxiety, benign prostatic
more than 20,000 men, those who consumed more than one fish hyperplasia, vaginitis, obesity, and dry eyes. Flaxseed oil contains
serving weekly had 52% less risk of sudden death compared with the omega-3 fatty acid ALA, linoleic acid, and oleic acid. Linoleic
those consuming fish less than once monthly. 44,45 acid and ALA are required to maintain cell membrane structure.
A systematic literature review of various lifestyle interventions ALA is associated with lower incidence of cardiac disease and im-
to reduce blood pressure supports the use of fatty fish to reduce proved outcomes in cardiac patients. 62 Flaxseed oil might de-
blood pressure in hypertensive individuals. 46 A meta-regression crease platelet aggregation. 62,63 Linoleic acid is an omega-6 fatty
analysis of 36 randomized trials endorsed the efficacy of fish oil acid; it possibly reduces the risk of ischemic stroke. 64 Flaxseed oil
in reducing blood pressure. 47 Median fish oil intake was 3.7 g may have anti-inflammatory effects; this in turn could slow the