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.
