Benefits of Fish Oil Supplementation

Recently there has been many health claims for fish oil, (which contain omega-3 fatty acids) in conditions from Alzheimer disease to macular degeneration. However, many of these claims, although exciting, are based on indirect evidence. But the evidence is with regard to coronary heart disease prevention, and the American Heart Association recently issued guidelines for the intake of Omega-3 oils.

Much of the interest in fish oil comes form the pioneering study of Greenland Eskimos almost 30 years ago. Although, what was discovered was that while the diet of these Eskimos was very high in fat, their rate of coronary artery disease was extremely low. This landmark study has spawned numerous other research studies, leading to recommendations of various public health organizations for increased intake of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the two major fish oils.

Fish do not actually produce EPA and DHA. Rather, these oils are produced by single-celled marine organisms that fish eat. Therefore, these fatty acids are essential for fish as well as for humans.

A third omega-3 fatty acid, alpha-linolenic acid (ALA), is found in certain plant oils but not in fish. The richest available plant source is flaxseed oil, which contains about 55% ALA in weight. Other sources include perilla oil and canola oil. Certain nuts, primarily walnuts, contain some ALA. But ALA is very poorly converted to EPA and DHA in the body, and doesn’t have nearly the cardiovascular health benefits of the primary omega-3 atty acids.

What are the benefits of OMEGA-3 fatty acids?

EPA and DHA appear to reduce the susceptibility of the heart to fatal rhythm disorders, or arrhythmias, which could otherwise lead to sudden cardiac death. In large doses they can lower serum triglycerides. Moreover, they inhibit platelet function, thereby acting as a mild blood thinner, preventing platelets from clumping together which could otherwise lead to blood clots and heart attacks. A recent study has shown that 1.5 g of EPA/DHA may well make carotid artery plaques more stable, thereby preventing strokes.

Key points to remember: The “oilier” the fish, the more omega-3 fatty acids it contains. Oily fish include tuna, sardines, salmon, mackerel, and herring. The American heart Association recommends about 1 g of omega-3 fatty acids per day for those with known coronary heart disease. People with no known heart disease should eat oily fish at least twice a week, or about 500 mg of EPA/DHA per day. Much higher intake, ie, from 2 to 4 g per day, is needed to lower triglyceride levels. This should be done in consultation with a physician. In general, eating fish or taking fish oil capsules does not present a health hazard. There remains, however, the concern of mercury toxicity, since mercury can bioconcentrate in fish at the top of the marine food chain. This has prompted the FDA to issue an advisory regarding four species of fish: king mackerel. shark, swordfish, and tile fish. Since mercury toxicity is mainly a concern for fetuses and breast-fed infants, the FDA advice is specifically targeted at pregnant women, those wanting to become pregnant, and nursing mothers. • Fish oil capsules contain no mercury. Mercury is water- soluble, not oil-soluble, so when the oil is extracted from the fish, the mercury (and the lead, cadmium, and other heavy metals) stay behind in the flesh of the fish. There is little evidence that one of the omega-3 fatty acids is more cardioprotective than the other. Therefore, both EPA and DHA are needed. There is emerging evidence for noncardiac benefits of Omega-3 fatty acids. Benefits are seen in the treatment of rheumatoid arthritis, lupus, and ulcerative colitis. The cardioprotective effects are unequivocal, however, and Omega-3 fatty acids are indeed the first supplement ever to be recommended by the American Heart Association.

Dr. Elkin is a board-certified internist, cardiologist and anti-aging medical specialist.

VERY IMPORTANT NOTE / DISCLAIMER: I am offering—always—only general information and my own opinion in these articles. Always contact your physician or a health professional before starting any treatments, exercise programs or using supplements.
©Howard Elkin MD FACC, 2012

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