CHICAGO (Reuters) - Sea bass? Flounder? Eat up. There's evidence, scientists said Tuesday, that ocean fish pose little risk, even to children and pregnant women, from low levels of mercury they pick up in the aquatic food chain.
The report came from a study in the Seychelles, the Indian Ocean island republic whose 65,000 residents eat nearly a dozen ocean fish meals a week and whose bodies have mercury levels 10 times those found in most people in the United States.
Researchers looked at 711 children born to women who ate large quantities of mercury-tainted ocean fish during their pregnancies and followed the children to age five and a half. They found no evidence of impaired mental development in the toddlers -- the main threat that mercury has been theorized to pose at levels found in ocean fish.
``The benefits of fish consumption that are widely appreciated are such that our study would suggest we should not be worried about continuing to eat it,'' Philip Davidson, chief author of the University of Rochester study, told Reuters.
He said mercury generally shows up in ``very low doseages'' in fish. In the United States, the allowable level for fish sold commercially is 1 part per million. The fish tested in the Seychelles, the study said, had mercury levels of from .004 to .75 parts per million.
``We look at the Seychelles people as a sentinel population,'' added Gary Myers, another member of the research team, in a news release issued by the university.
``If somebody who eats fish twice a day does not show effects from mercury exposure, it's unlikely that somebody who eats fish twice a week will be affected,'' he said. ``And the fish they eat in the Seychelles contains the same amount of mercury as fish sold at supermarkets and eaten in the United States.''
Added Davidson: ``What we found in the Seychelles is applicable to every woman, every man and every child around the world who eats ocean fish.''
Thomas Clarkson, the study's principal investigator, said ''eating lots of ocean fish isn't much of a hazard compared to missing out on the benefits from not eating fish ... overstating the almost negligible risk of mercury could adversely affect millions of people who face the risk of heart disease.''
The study, published in this week's Journal of the American Medical Association, said the children studied were developing ''without any detectable adverse influence of (mercury). In fact, the association seen in some of our test results indicated improved performance and may support the nutritional benefits of fish consumption.''
The journal also carried an editorial from an expert at the U.S. Environmental Protection Agency who cautioned that the study's findings were preliminary and that additional evaluations using more sensitive tests of development were needed ``before firm conclusions can be drawn.''
``Until then, women of childbearing age who eat fish nearly daily need to be aware of the level of mercury contamination in the fish they consume,'' she added.
The study found no adverse developmental effects in the toddlers when they were evaluated in several areas including cognition, language, reading and arithmetic, visual-spatial abilities and social and adaptive skills.
The research team said its findings do not apply in the United States to fish caught in lakes and rivers for which consumers should follow local advisories about mercury and other contamination.
It also said its findings were at odds with a Danish study that did find developmental problems with fish-eating children in the Faroe Islands. It said the difference may be that the Danish study involved a population that ate whale, which may pose a different problem.
Inorganic mercury discharged into lakes, streams and other waterways or dissolved into water from industrial sources such as coal-fired power plants is converted to methylmercury and winds up in the aquatic food chain. At high levels of concentration, methylmercury can be deadly.
Concern arose over it the United States during the 1970s when high concentrations were found in Great Lakes fish that also carry other contaminants.
The report said public health disasters in Minamata and Niigata Japan caused by fish highly contaminated with methylmercury from an industrial source and in Iraq caused by bread containing a methylmercury fungicide pinpointed the danger it poses to children at high concentrations.