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NEW YORK (Reuters Health) - Older adults who regularly eat
fish may have a lower risk of subtle brain damage that
contributes to stroke and dementia -- as long as the fish isn't
fried -- researchers reported Monday.
In a study that followed 3,660 adults age 65 and older,
Finnish researchers found that those who ate more fish were
less likely to show certain "silent" brain infarcts -- tiny
areas of tissue that have died because of an insufficient blood
supply -- on an MRI scan.
The tissue damage is considered silent, or "subclinical,"
because it causes no obvious symptoms and can only be detected
through brain scans. It can, however, raise a person's
longer-term risk of having a stroke or developing dementia.
Among older adults in the current study, those who said
they ate tuna and "other" baked or broiled fish at least three
times per week were one-quarter less likely than those who
rarely ate fish to have subclinical brain infarcts at the
study's start.
Fish eaters also tended to be less likely to develop new
infarcts over the next five years.
No such benefits were linked to consumption of fried fish,
however, the researchers report in the journal Neurology.
While the study cannot conclusively point to the reason for
the brain benefits, it's likely that omega-3 fatty acids --
healthy fats found mainly in oily fish -- play a key role,
according to Dr. Jyrki K. Virtanen and colleagues at the
University of Kuopio.
When the researchers estimated study participants' intake
of two major omega-3 fatty acids -- EPA and DHA -- they found a
link between higher intake and lower risk of silent brain
infarcts.
In addition, the researchers note, the lack of a protective
effect from fried fish may stem from the fact that foods like
fish burgers and fish sticks are typically made from fish low
in omega-3.
Overall, the findings add to evidence that fish rich in
omega-3 fats -- like salmon, mackerel and albacore tuna -- may
have "important health benefits," the researchers write.
"Previous findings have shown that fish and fish oil can
help prevent stroke, but this is one of the only studies that
looks at fish's effect on silent brain infarcts in healthy,
older people," Virtanen said in a written statement.
"More research is needed as to why these types of fish may
have protective effects, but the omega-3 fatty acids EPA and
DHA would seem to have a major role." Virtanen added.
Silent brain infarcts can raise a person's risk of both
stroke and cognitive decline. It's estimated that about 20
percent of adults age 65 and up who are free of silent infarcts
will develop at least one within five years.
The American Heart Association recommends that all adults
strive to eat at least two fish meals per week, preferably
fatty fish, for the sake of their cardiovascular health.
SOURCE: Neurology, August 5, 2008.
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