Mercury Levels

I love fish and seafood but am concerned by the recent articles I've read about the high level of mercury in most fish. What kinds of fish are safe to eat regularly and which ones should I stay away from? —S.H., Lancaster, California

The greatest concern with mercury in fish is the damage it may cause to the developing nervous systems of unborn children, infants and toddlers. For adults and older children, there is a small chance of neurological health issues as mercury accumulates in the body. Therefore, the Food and Drug Administration has issued seafood consumption guidelines for the general population…for women of childbearing years who are or may become pregnant or are nursing…and for small children. Their recommendations are as follows: It's all right for the general population to eat up to 2 pounds of various fish per week…childbearing women should limit their intake to 12 ounces of cooked fish a week…while small children should be limited to less than 4 ounces of fish a week. The mercury level in commercially caught fish varies greatly, depending on the species. Mercury levels are highest in fish that are large and long-lived. The FDA reports the highest mercury levels are in shark, swordfish and king mackerel. These fish are high on the food chain and accumulate mercury from feeding on smaller fish during their long lives. The FDA recommends that the general population should limit consumption of these fish to one serving per week, while childbearing women and infants should avoid them altogether.

Seafood with moderate levels of mercury include grouper, sea trout, bluefish, marlin, orange roughy, red snapper, fresh or frozen tuna, canned albacore tuna and lobster. Most people should limit servings to twice a week; children and childbearing women should not eat these fish more than once a week. The lowest levels of mercury are found in canned light tuna, salmon, pollack, haddock, cod, halibut, mahi mahi, catfish, flounder, sole, tilapia, farm-raised freshwater trout, herring, sardines, shrimp, crabs, clams, oysters and scallops. Fortunately, these fish and seafood account for about 80 percent of the seafood consumed in North America. Some of the recent attention surrounding mercury levels pertains to changes in recommendations about tuna. The latest FDA research confirmed that larger tuna, such as albacore or white tuna, have a higher level of mercury than previously reported. This species of tuna is often sold as steaks at the grocery store or in restaurants and is the type used in premium canned tuna. This tuna falls in the moderate mercury level category, where consumption should be limited. Smaller tuna, such as skipjack and yellowfin, fall into the lowest mercury level category. These tuna are the species used in canned tuna labeled chunk light and present minimal mercury concern. Recreational sport fish are a different story. Each state issues health statements about fish caught in local waters based on environmental testing. Contact your state’s Department of Natural Resources or cooperative extension for more information. Seafood remains an excellent source of low-fat protein, heart-healthy omega-3 fatty acids and minerals such as calcium and zinc. But it is best to eat a variety of fish, concentrating on those at the lower end of the mercury scale.