Mercury in steady seafood diet may cause
long-term damage in children
February 06, 2004
BOSTON - Pregnant women who
eat seafood high in mercury could be causing
permanent damage to their children, researchers
An international group of researchers found
diets high in contaminated seafood can cause
permanent brain and heart damage in the unborn.
tuna tends to have more mercury than wild
"We found that both prenatal and postnatal
mercury exposure affects brain functions and
that they seem to affect different targets in
the brain," said Philippe Grandjean of
the department of environmental health at the
Harvard School of Public Health.
"The fact that the current exposure has
an additional effect, despite the low mercury
concentrations is worrisome, especially for
communities where seafood constitutes an important
part of the diet," Grandjean added in a
The researchers studied more than 1,000 mothers
and children living in the Faroe Islands, in
the North Atlantic Ocean between Norway and
The islands' economy is focused on fishing
and the population's diet includes a high intake
of seafood and whale meat.
The researchers measured mercury in the cord
blood when the children were born, as well in
hair samples taken at ages seven and 14.
Grandjean and his colleagues put electrodes
on the children's heads to measure electrical
signals in the brain.
The scientists found the higher the mother
and child's mercury levels were at birth, the
more they saw delays in brain signalling.
The brain changes also seemed to lead to poorer
heart function, such as subtle differences in
controlling blood pressure.
The study appears in Friday's issue of the
Journal of Pediatrics.
The report comes at the same time as a U.S.
Environmental Protection Agency study doubled
its estimates of how many newborns have unsafe
levels of mercury in their blood.
Regulatory agencies have to balance concerns
about mercury exposure with the heart-healthy
nutrients in fish.
Scientists continue to debate whether low levels
of mercury in seafood are harmful and if results
from people eating a whale-rich diet extends
to other populations.
by CBC News Online staff