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Beware High Mercury Fish

fish and saladFish have been recommended as an important part of a healthy diet because of their high-quality protein, are low in saturated fat, and contain omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Incorporating a variety of fish can contribute to heart health.

However, nearly all fish contain traces of mercury. Some researchers believe consuming fish with high mercury levels will diminish all potential health benefits. Some studies have actually suggested an increased risk of cardiovascular disease associated with mercury levels in fish, whereas other studies could not find any relationship between elevated mercury and risk of heart disease. This controversy has caused much discussion on what amount of fish is safe to eat without having harmful effects in the body.

Mercury exists in various forms and people are exposed to each in different ways.  Mercury is emitted to the air by human activities and from natural sources.  Mercury is released into the atmosphere in one of three forms: elemental mercury, particle-bound mercury, oxidized mercury; and in nature exists as elemental mercury, inorganic mercury, and organic mercury.  Microorganisms can convert inorganic to organic mercury which is toxic and can be consumed by small animals, incorporating it into the food chain.

Mercury levels seen in fish is a highly potent neurotoxin in the body.  For most people, the risk from eating fish containing mercury is not a health concern. Yet, some fish and shellfish contain higher levels of mercury that have shown to be harmful and detrimental to developing fetuses, infants, and children’s neurological development and function. The risks from mercury in fish depend on the amount eaten and the levels of mercury in the fish. Therefore, the Food and Drug Administration and the Environmental Protection Agency (EPA) advise women who may become pregnant, are already pregnant women, nursing mothers, and young children to avoid some types of fish and eat fish and shellfish that are lower in mercury.

So what kind of fish should be avoided? Fish that are long-lived, predatory, and high on the food chain typically contain higher amounts of mercury. Some of these higher mercury fish include: tilefish, swordfish, king mackerel, and shark. You don’t have to completely avoid these fish, you just need to make sure that you eat these fish very sparsely.  For more information check out the EPA website, which can provide you with more details and a complete list of these fish.

June 22nd, 2009