Pregnant women warned of tuna risk

Pregnant women were advised yesterday to limit the amount of tuna they eat because of concern about levels of mercury in the fish. Mothers who breastfeed and women hoping to become pregnant were also told to follow the advice.

The guidance was issued by the Food Standards Agency after a survey last year into levels of mercury in commonly eaten fish was reviewed by the independent Committee on Toxicity, which advises the Government. Pregnant women and children are already urged not to eat any shark, sword-fish or marlin because of they contain levels of mercury, which can harm the nervous system of babies.

The agency said there was a "small risk" from mercury in tuna affecting unborn children and new babies, and women in those categories should eat no more than one tuna steak a week or two tins of tuna, each weighing 140g drained – the equivalent of six rounds of sandwiches or three tuna salads. The advice does not apply to children and other adults.

The survey found the levels of mercury in tinned and fresh tuna were less than a thousandth of a gram. Shark, swordfish and marlin had about six times the levels of mercury of tinned tuna and about three times the levels of mercury in fresh tuna.

Dr Andrew Wadge, safety director at the Food Standards Agency, said: "It is unlikely that many pregnant or breastfeeding women eat more than the recommended amounts of these fish every week. But for any that currently do, it would be a sensible precaution to change their diets slightly."