Antioxidant Supplements
Don't Reduce Stroke Risk
Vitamin E and beta-carotene supplements
do not seem to have any preventive effects on stroke in middle-aged
men who smoke, Finnish and US researchers report.
The findings come from further
analysis of data from a Finnish study, the Alpha Tocopherol, Beta
Carotene Cancer Prevention Study, a trial involving more than
29,000 male smokers between 50 and 69 years. It was originally
intended to see if these antioxidants cut the risk of lung cancer.
Recently, researchers reported
that the supplements did not protect the men against heart disease.
Now, Dr. Markareetta E. Tornwall
of the National Public Health Institute, Helsinki, and colleagues
report in the American Heart Association's journal Stroke on the
effects of vitamin E and beta-carotene on stroke rates among the
participants.
The subjects had been randomized
to take vitamin E, beta-carotene, both or placebo daily for 5
to 8 years. Over this period, vitamin E reduced the risk of stroke
due to blockage of arteries supplying blood to the brain by 14
percent. On the other hand, beta-carotene increased the risk of
stroke due of bleeding in the brain by 62 percent.
During the 6 years after the study
ended, 1327 men had strokes.
The odds of an artery-block stroke
was increased by 13 percent in those who had taken vitamin E,
and reduced by 3 percent for those given beta-carotene.
The risk of bleeding stroke was
increased by 1 percent in the vitamin E group, but by 38 percent
for beta-carotene supplementation.
The researchers conclude that the
apparent increased risks of bleeding "are difficult to explain
because of the absence of any plausible mechanism."
SOURCE: Stroke, August 2004.
Reference
Source 89
August 13, 2004
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