Studies Tip Scales

Go ahead, have fish

Seafood benefits outweigh the risks, scientists decide

October 18, 2006|By Dennis O'Brien | Dennis O'Brien,Sun reporter

Confused about fish? Just eat it, the government says - unless you're a child, you're pregnant or you're a nursing mother.

And even then, you can eat most of it.

That's the advice from two scientific teams that released reports yesterday designed to help consumers balance the health benefits of fish against the risks from trace amounts of mercury, PCBs, dioxin and other toxins. The reports say that seafood is not only safe but highly recommended, with a few caveats for youngsters and women of child-bearing age.

The Institute of Medicine, a national panel of distinguished physicians and researchers that advises the country on health matters, produced the report in an effort to clear the air after years of studies suggesting that some seafood is not safe.

The study recommends that children under 13 and women who are pregnant, nursing or could become pregnant should limit their intake of tuna and avoid eating large, predatory fish such as shark and swordfish. These fish tend to have higher concentrations of mercury than other seafood.

A Harvard study published in The Journal of the American Medical Association came to the same conclusion. And both reports said the risks of toxins in fish might have been overstated.

"It all shows that health scares about seafood consumption are not based on reliable science and are largely overblown," said William T. Hogarth, director of the National Oceanic and Atmospheric Administration's Marine Fisheries Service. NOAA commissioned the report.

"Consumers are being confronted with a dilemma," said Malden Nesheim, the retired Cornell University professor who served as chairman of the Institute of Medicine's panel. "People are being told that seafood is good for them, but fish advisories are warning people not to eat certain fish."

Toxins such as mercury have been a major concern, scientists agree. Mercury occurs naturally in the environment, with thousands of tons released into the atmosphere each year by the burning of fossil fuels and the degassing of Earth's crust and oceans, federal officials say.

Trace amounts from the atmosphere dissolve in water, where it is transformed into methyl mercury and absorbed by fish through their gills and diet. Larger, predatory fish develop more concentrated levels of methyl mercury when they eat their prey, experts say.

Meanwhile, the IOM said evidence that fish consumption reduces the risk of diabetes, cancer, Alzheimer's and other ailments might be overstated - but there is solid evidence that it reduces the risk of heart disease. The Harvard study confirmed those findings.

"Avoiding seafood because of a health concern is not the right answer," said Dr. Dariush Mozaffarian, the lead author of the Harvard study. "We were surprised by how little evidence there is for some of these reported harms."

Experts say that, from a health perspective, there is no single best fish. And being well-informed is no guarantee of an easy choice the next time you're at a fish market or seafood house.

Salmon, for example, contains high levels of omega-3 fatty acids that can help prevent heart attack and stroke. But salmon can also have higher levels of pollutants than many other fish. Likewise, long-lived predators such as swordfish, shark and tilefish are good sources of protein, but they have mercury levels too high to be safe for pregnant women and nursing mothers. Fish can be mislabeled, the researchers noted, and a species caught in one ocean can carry different toxins than the same species caught elsewhere.

"It's become a very confusing area for the consumer," said Robert Lawrence, a researcher at the Johns Hopkins Bloomberg School of Public Health who was not involved in the studies but did review the IOM report.

Health benefits associated with omega-3 fatty acids from fish have been widely documented. The Harvard study noted that a report first detailing the relative health of Greenland Eskimos traced their longevity to a fish rich diet - in 1980.

Yesterday's studies are unlikely to end debate over the safety of seafood and the best ways to harvest it, experts say.

"One issue left unaddressed is that people need to make decisions based not just on their own health, but on the overall future and abundance of the fisheries," said Rebecca Goldburg, a senior scientist with Environmental Defense, a nonprofit advocacy group. "Many fisheries, they're being exploited to the point where it's going to be hard to find a lot of these fish."

Meanwhile, representatives of the seafood industry embraced the findings. "The bottom line is that the benefits outweigh the risks," said Anne Forristall Luke, president of the U.S. Tuna Foundation, which represents the nation's largest tuna distributors.

More than 11 million people have been scared away from buying canned tuna in recent years because of concerns about mercury, and market studies show that most of those are from low-income households that can't afford higher-priced fish, she said.

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