LONDON, United Kingdom, May 13, 2002 (ENS) - Pregnant women, women who intend to become pregnant, infants and children under 16 years of age should avoid eating shark, swordfish and marlin due to high levels of mercury in these fish, the UK Food Standards Agency said Friday.
The agency carried out a survey that analyzed 336 fresh, frozen and processed sea fish and shellfish for mercury, but levels in fish other than shark, swordfish and marlin did not give cause for concern.
Levels of mercury in marlin were found to be somewhat lower, but about twice as high as mercury levels in orange roughy, the next most mercury contaminated species.
This warning parallels an advisory issued by the U.S. Food and Drug Administration (FDA) in January 2001. The FDA advises pregnant women and women of childbearing age who may become pregnant not to eat shark, swordfish, king mackerel, and tilefish. The FDA also recommends that nursing mothers and young children not eat these fish.
Health Canada advises Canadians to limit consumption of shark, swordfish and fresh and frozen tuna, to one meal per week. Pregnant women, women of child-bearing age and young children should eat no more than one meal per month, the Canadian agency warns.
Methylmercury is known to be neurotoxic to humans as well as to animals. Methylmercury can harm the nervous system of an unborn child. Infants and children may also be at greater risk of mercury poisoning because they eat more food relative to their body size than adults.
Ingesting high levels of methylmercury when pregnant could lead to impaired mental skills in the unborn child, such as attention and memory problems, and lack of physical coordination in childhood, the agency said.
In adults, first sign of mercury poisoning is most likely to be a creeping or tingling sensation in the skin. The agency said that unless exposures are very high these effects are likely to be transient.
Occasionally eating shark, swordfish and marlin as part of a balanced diet is unlikely to cause harm to other adults. But as a precaution, the agency is advising people not to eat more than one portion of these fish each week.
Mercury is a naturally occurring element found in soil and rocks, and in lakes, streams and oceans. In addition to natural sources, mercury is released into the environment by human activities such as pulp and paper processing, mining operations, and burning garbage and fossil fuels.
The independent expert Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment will consider the results of the survey at its June meeting and may issue further advice.