Eat lower-mercury fish

Shark, swordfish, king mackerel and tilefish should be off the menu for pregnant women, nursing mothers, children and women who may become pregnant because they contain too much mercury, the US government said on Friday.

Health officials said adults can eat up to 340 grammes - two average meals - a week of seafood that was lower in mercury such as shrimp, canned light tuna, salmon, pollock and catfish. Only half that amount of albacore, or "white" tuna, should be eaten per week.

Consumer and environmental groups said the government had soft-pedalled the risk from eating large amounts of white tuna.

"Tuna is a really popular fish and some people eat a whole lot of it," said Diana Zuckerman of the National Centre for Policy Research for Women and Children.

While fish and shellfish are a good source of protein, nearly all seafood contains traces of methylmercury.

High levels of mercury in the bloodstream of fetuses and young children can impair development of the nervous system.

In a joint advisory that updated guidelines issued separately, the Food and Drug Administration and the Environmental Protection Agency said shark, swordfish, king mackerel and tilefish should not be eaten by pregnant women, nursing mothers, children and women who may become pregnant. Methylmercury levels are highest in longer-lived, large fish.

The FDA and EPA said adults could eat up to 340 grammes per week of fish low in mercury. But they should eat no more than 170 grammes of white tuna or fish caught by family and friends.

The same guidelines on weekly consumption apply to children but they should be given smaller portions, officials said.

Fish sticks and fish sandwiches commonly are made using fish low in mercury, FDA said. Tuna steaks are higher in mercury and should be limited to 170 grammes a week.

On Thursday, the European Union's food safety authority recommended pregnant women limit consumption of fish, including swordfish and tuna, due to high mercury levels.

US consumer activists said as a rule, light tuna had higher levels of mercury than shrimp, salmon, pollock and catfish, which were listed together as "five commonly eaten fish that are low in mercury".

An EPA researcher has estimated about 630,000 US children are born annually with unsafe levels of mercury in the blood.

"What concerns me is how they buried this tuna information," said Ms Zuckerman, by putting it towards the bottom of the one-page advisory.

White tuna contains three times as much mercury as light tuna, said Jane Halloran of Consumers Union. "It is essential FDA warn women of child-bearing age to limit their intake of albacore white tuna," she said.

The Environmental Working Group said the FDA "has actually made a bad situation worse, by encouraging consumption of albacore tuna at clearly unsafe levels." EWG said some white tuna can contain excessive amounts of mercury.

Trade groups representing the food industry said the new advisory showed the benefits of fish as well as how to limit exposure to mercury. The US Tuna Foundation described tuna as "nature's healthy fast food," low in fat and high in nutrients.