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Two new U.S. studies say the nutritional
benefits of eating fish outweigh the potential hazards from environmental
contaminants. Some environmental and consumer groups dispute the
finding.
You may have heard that fish contain mercury and other compounds called
PCBs and dioxins that can be harmful physically. But Harvard University
doctors and a separate panel of private experts reporting to the U.S.
government say eating fish regularly is very healthy, especially for the
heart.
One of the authors of the Harvard study, Dariush Mozaffarian, puts it
this way.
"The benefits of eating fish are far greater than the potential risks.
If you eat a fish and it has some mercury in it, you might be getting less
benefit from that fish than if it did not have mercury in it, but the
overall benefit is still positive," he said.
The Harvard team says that benefits are great even for women of
childbearing age if they avoid certain fish that are likely to contain
mercury levels dangerous to fetuses. The second study lists them as
predatory fish with long lifespans, such as swordfish, shark, and
tilefish.
This study is by the U.S. Institute of Medicine, a branch of the
National Academy of Sciences that uses private experts to investigate
issues for the U.S. government. Like the Harvard study, it is a summary of
recent major research on fish consumption.
Both reports note that consumers are faced with conflicting evidence
about eating fish. It is a good protein source containing the type of fat
considered healthy for the heart. But some species absorb toxins present
in the environment, causing confusion about the role of fish in a healthy
diet.
So Institute of Medicine committee member David Bellinger, a Harvard
nerve specialist not associated with the Harvard study, offers this
advice.
"Because of the uncertainties, especially on the risk side, consumers
should consume a variety of fish because the fish that contain one
contaminant may not be the same fish that contain another contaminant, so
that by consuming a variety of species, the benefits can be maximized, but
the overall risk profile can be managed," he noted.
A U.S. environmental group disputes the findings. The National
Environmental Trust argues that the two studies ignore evidence that
chemicals used as flame retardants are also pervasive in the environment
and contaminate fish. In addition, the organization's vice-president for
marine conservation, Gerald Leape, says boosting fish consumption would
strain wild fish populations that already suffer from overfishing and
cause expansion of fish farms where contaminants are more prevalent.
"They have left out a true examination of the role of contamination,
and there was no effort to take into account the ecological impacts not
only of wild fish captures, but also of aquaculture farming," he said.
Another group, the Physicians Committee for Responsible Medicine, warns
that fish and shellfish are
significant sources of cholesterol, a factor in heart disease. It points
out that shellfish in particular have more cholesterol than an equivalent
amount of beef.
But Harvard University's Dariush Mozaffarian counters with one of the
main findings of his study.
"We found that a modest intake of fish, about one or two servings per
week, was enough to reduce the risk of dying from a heart attack by about
35 percent, which is a considerable effect," he explained. | 
