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News Bites: Fish as Food for the Brain & Exercise
for Eye Health
DHA, Fish Lower Risk for Alzheimer's
Coldwater, fatty fish are a concentrated
source of the omega-3 fats docosahexaenoic acid (DHA)
and eicosapentaenoic acid (EPA).
Population health studies have consistently shown positive health
effects from fish consumption and, now, a study published in the
November issue of The Archives of Neurology, links greater fish
intake to a lower risk of developing Alzheimer's and other dementias
(1). And in this study, DHA
was most important for cutting risk.
Using data from the Framingham Heart study,
researchers followed about 900 healthy participants for an average
of more than 9 years. During that time, 99 people developed dementia
including 71 cases of Alzheimer's. Researchers quantified the
amount of DHA
and fish the participants typically consumed by dietary questionnaires,
and measured the level of fatty acids in their blood.
DHA Cuts Risk of Dementia by Nearly 50%
The top 25% of study volunteers with the
highest blood levels of DHA
reduced their risk of developing dementia by 47%. They were about
half as likely to develop dementia as the 75% of participants
with lower levels of DHA
in their blood. The risk reduction was seen even after controlling
for other known or suspected risk factors for dementia such as
smoking, overweight, high blood pressure and diabetes.
Participants who ate two or more servings
of fish weekly reduced their dementia risk by 39%, while those
who ate less had no risk reduction.
According to the study's authors, the observation
that DHA
seems to be key in lowering dementia risk is consistent with earlier
data showing high levels of DHA
in healthy brain tissue and low levels in the brains of people
with Alzheimer's. The next step will be to conduct placebo controlled
trials of DHA
in people who don't yet have Alzheimer's to see whether DHA
can help protect against this disease.
Active Lifestyle Could Protect Against AMD
Exercise may help protect against age-related
macular degeneration (AMD) according to the results of a large
study supported by the NIH and published in the British Journal
of Ophthalmology (2). The authors examined the relationship between
physical activity and AMD because heart disease and AMD appear
to share common risk factors. And regular exercise, as we all
know, is good for the heart and arteries.
Participants in the Beaver Dam Eye Study
were followed for 15 years. During that time they were given eye
exams periodically, and they filled out questionnaires at the
beginning of the study to assess their level of activity. They
were asked how many flights of stairs they climbed daily, how
many city blocks they walked each day, and how often each week
they engaged in physical activity that involved working up a sweat.
Compared with sedentary people, those who
participated in regular activity 3 times weekly were less likely
to develop wet AMD. Those with an active lifestyle - defined as
engaging in an activity that resulted in sweating 3 or more times
each week - reduced their risk of wet AMD by 70%. Walking 12 or
more blocks daily lowered that risk by 30%.
Walk Daily, Put More Fish on Menu
Can't get to the gym or participate in vigorous
exercise? Try walking at least a mile daily. Though each city
and each block vary in length, walking 8-12 city blocks is roughly
equivalent to a mile. It's certainly good for heart and may help
your eyesight as well.
For better mental function as we age, remember
that fatty fish is best, and frying fish can cause some deterioration
of its DHA
content. You can also consider augmenting your intake of DHA
and EPA
with supplemental fish oil.
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