Almost all fish and shellfish contain a small amount of mercury. Mercury that moves from the air into bodies of water where fish live and absorb the toxin is called methylmercury. Mercury in tilapia and other fish and seafood is monitored by the U.S. Food and Drug Administration (FDA). Fish is considered an excellent source of protein, omega-3 fatty acids and other important nutrients. Mercury or methylmercury can pose a particular problem for children and women who are pregnant, nursing or who may become pregnant.
U.S. Farm-raised Tilapia
Tilapia is often farm-raised and is considered to pose a lower mercury risk than many other types of fish. Farm-raised tilapia from the U.S. is considered the safest source. Other good alternatives include farm-raised tilapia from Brazil, Costa Rica, Ecuador and Honduras. Most tilapia available in the U.S. is raised in China and Taiwan, which have less stringent management and greater pollution risks. Packaging regulations in the U.S. require the country of origin be stated on fish products, so look for "American tilapia."
Eating Fish During Pregnancy
Children and women who are pregnant, nursing or who may become pregnant should limit their consumption of fish and shellfish to no more than 12 ounces per week and avoid fish that contains high levels of mercury. Fish that's low in mercury and considered safe includes tilapia, shrimp, canned tuna, salmon, pollock and catfish. Albacore tuna contains higher levels of mercury than canned tuna and should be restricted to no more than six ounces per week. Be careful consuming fish caught in local waterways as it may contain unsafe levels of mercury and other pollutants. State fish and game agencies can provide detailed recommendations about which locally caught fish is safe to eat and in what quantities.
What About Sushi?
Although eating raw fish in sushi, sashimi and ceviche is popular, it poses a significantly higher health risk than cooked fish. Raw fish may contain parasites, bacteria and viruses that can cause illness. Raw fish should not be consumed by children or women who are pregnant, nursing or who may become pregnant. Cooking to recommended temperatures kills parasites and other microorganisms but doesn't lower levels of contaminants such as mercury.
Fish You Should Avoid
The FDA recommends that shark, swordfish, king mackerel and tilefish be avoided because of high levels of mercury. These fish may also contain other contaminants like pesticides and industrial chemicals such as dioxin and PCBs. The Environmental Defense Fund, a nonprofit advocacy group, recommends against consuming any of the above fish species as well as bluefin tuna, walleye and marlin.