Nikki's Nutrition

Tuesday, March 07, 2006

Sushi is Bad for You???

In an article I found on yahoo news, I found a disturbing study that was done by the group ""...

Turns out, there's more mercury in more types of fish than I thought.

The article says that sushi has more mercury than is good for you...

So I did a little looking and asking around...

I asked the question, "Does all fish have mercury?" to the kind people on the yahoo groups... The following is the answer that was the most complete:

Mercury in Fish

What is mercury and where does it come from?

Mercury is released into the environment from natural deposits in rocks, volcanoes, and soils. It is also released into the environment when power plants burn coal, incinerators burn mercury containing wastes, and during the production of other industrial chemicals. Airborne mercury can travel in the atmosphere for years. It eventually attaches itself to dust and water particles and enters waters with rain and runoff.

How does mercury get into fish?

Mercury is found, usually at extremely low concentrations, in virtually all waters. Naturally occurring bacteria that process sulfate in aquatic systems take up mercury and convert it into methyl-mercury through a metabolic process. These bacteria may be consumed by the next higher level in the food chain and pass on their burden of methyl-mercury. Because animals accumulate methyl-mercury faster than they eliminate it, animals consume higher concentrations of mercury at each successive level of the food chain. This process, called biomagnification, results in high concentrations of mercury in long-lived predatory fish at the top of the food chain.

What types of fish contain the least mercury?

Nearly all fishes and shellfish contain at least trace amounts of mercury. In freshwaters, small, short-lived species such as sunfish (bream), brown bullhead, and black crappie (specs) generally have low concentrations of mercury. Largemouth bass and other long-lived predatory fish have higher concentrations of mercury; however, smaller largemouth bass have less mercury than larger individuals. In marine waters, shorter lived species such as striped mullet, pompano, sheepshead, common dolphin, gray snapper, gulf flounder, and southern flounder generally have much lower concentrations while king mackerel, swordfish, and sharks tend to have the highest concentrations. Ultimately, mercury concentrations in fishes depend on diet and lifespan: those that consume other fish and live longest have the highest mercury concentrations.

Where is mercury found in fish?

Since mercury accumulates in the muscle tissue of fishes, which is the part you eat, trimming excess fat and skinning do not reduce the amount of mercury you consume. The only way to reduce mercury consumption is to eat fish from less contaminated water bodies and to select species that are lower in mercury. By choosing a variety of fish low in mercury from different water bodies and avoiding eating only one type, anglers can enjoy catching and eating fish from waters.

Fish and Wildlife Research Institute


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