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Fish is rich in
omega-3 fatty acids believed to lower the risk of heart disease,
however a new study questions whether consuming fish contaminated
with mercury may actually increase the risk of heart disease
as well as reduce other potentially healthy benefits.
A previous study
found a link between heart disease and increased mercury levels
in men who ate contaminated fish. The new study, which involved
684 men who had previously had a heart attack and 724 men
who had not, investigated this further. Levels of the omega-3
fatty acid DHA were measured from fat tissue and mercury levels
were measured from toenail clippings.
It was found that
men who had had a heart attack had 15 percent higher mercury
levels than men who had no history of heart disease. Also,
men with the highest mercury levels were more than twice as
likely to have had a heart attack as compared with men with
the lowest mercury levels, according to the study.
After mercury levels
were adjusted for, it was found that the higher a man’s
DHA levels, the lower his risk of having a heart attack. The
study points out that this furthers the accepted notion of
the protective benefits of consuming fish.
However, researchers
point out that pregnant women, or those who may become pregnant,
are currently advised by the U.S. Food and Drug Administration
to not consume fish with high mercury levels such as shark,
swordfish and mackerel. They study suggests that this advice
may also benefit the general adult population.
The
New England Journal of Medicine November 28, 2002;347:1735-1736,
1747-1754, 1755-1760
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