A new tuna warning for pregnant women

Pregnant women should not eat canned tuna because it may contain harmful levels of mercury, Consumer Reports magazine said last week, taking a more cautious approach than that recommended by the U.S. government.

Since March 2004, the Food and Drug Administration and the Environmental Protection Agency have recommended women who are pregnant, nursing or planning to become pregnant should eat no more than 6 ounces of albacore tuna a week. But the government says it is safe to eat up to 12 ounces -- the amount of fish in two meals -- per week of fish and shellfish low in mercury, such as shrimp, salmon, light tuna and catfish.

Consumer Reports said 6% of canned light tuna tested by the FDA “contained at least as much of the metal -- in some cases more than twice as much -- as the average albacore.” Most of the cans had only one-third as much mercury.

Jane Halloran, director of food policy initiatives for Consumers Union, said that because of concerns that both types of tuna showed instances of higher levels of mercury, the magazine decided to recommend pregnant women eat neither. Consumers Union publishes Consumer Reports.

High levels of mercury in the bloodstream may harm developing nervous systems, according to the FDA. Fish and shellfish are the main sources of mercury exposure for humans.

The U.S. Tuna Foundation trade group said the magazine was overreacting. It said the nutritional benefits of seafood easily outweighed the risk posed by “trace amounts of mercury” and said scientific research showed the federal guidelines on consumption were sound.