Monday, November 15, 2010
ROCHESTER, Minn. — The fats in fish — omega-3 fatty acids — reduce the risk of heart disease. But there is concern that contaminants present in fish could outweigh the health benefits. The November issue of Mayo Clinic Health Letter covers the latest information on the benefits and risks of eating fish.
Eating one or two servings of fish a week, especially salmon or other fish high in omega-3 fatty acids, could reduce the risk of dying of a heart attack by one-third. Research links consumption of omega-3 fatty acids to a decreased risk of abnormal heart rhythms that may lead to sudden cardiac death. Evidence also suggests that omega-3s may help lower triglycerides levels and decrease plaques growing in blood vessels.
But fish and shellfish also contain methyl mercury, a component of industrial air pollution that falls as acid rain. Fish ingest the mercury as they feed. Eating too much fish could increase the risk of accumulating toxic amounts of mercury.
For most adults, there's a large range between what's considered a normal mercury level and what's considered toxic. A person's age and life phase need to be considered when weighing benefits and risks of fish and shellfish consumption. The Food and Drug Administration (FDA) advises that young children and women who are pregnant or breast-feeding should avoid eating fish with the highest mercury contamination, specifically tilefish, shark, swordfish and king mackerel. For others, the FDA suggests two meals a week of fish that have the lowest mercury levels, such as salmon and pollock.
However, for adults in general, recent research suggests that higher weekly fish and shellfish consumption may be beneficial. The cardiovascular benefits from eating a variety of fish lowest in mercury levels far outweigh the risks for postmenopausal women and older men. That research recommends tilapia, pollock, flounder, shrimp, trout, herring, salmon, canned light tuna and cod can be eaten daily. The study recommends skipping swordfish and shark.
State and local health departments offer information on the safety of locally caught fish. In addition, the Environmental Protection Agency provides information on safe fish consumption.
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