Britons should restrict the portions of oily fish they eat each week, the Food Standards Agency (FSA) has indicated, in its latest guidance on food safety.
Its latest advice follows a year-long investigation into the risks and benefits of eating oily fish, which has concluded that eating too much could be dangerous to health. Its advice beforehand was that adults should eat at least two portions of fish a week, of which one should be an oily species.
However, the agency was concerned about the build-up of industrial pollutants in the flesh of oily fish species, leading it to set upper consumption limits for the first time.
FSA chairman Sir John Krebs said: "This review has reduced uncertainty about how many oily fish people can safely eat without the benefits being outweighed by the risks."
It concluded that men and boys, and women over child-bearing age or who do not intend to become pregnant, can eat as many as four portions a week. Girls and women who are likely to have a child, or who are pregnant or breastfeeding, should limit their intake to just two portions.
Tony Allan, founder of seafood restaurant chain Fish!, said: "It's sad that a food which has long been synonymous with good health and good eating is now sufficiently polluted that the FSA is having to place recommended limits on its consumption." However, the FSA stressed that, despite the alert, most people do not eat enough oily fish and should still eat more.
The alert follows the publication of an American study earlier this year, now refuted, which claimed that Scottish salmon contained very high levels of contaminants.