- WASHINGTON (www.nando.net) -- Vitamin E pills reduced prostate cancer risk
by a third and the disease's death rate by 41 percent in a study of thousands
of smokers, researchers report. The same study, in Finland, found that
a form of vitamin A had no effect on reducing cancer.
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- "There may be a pattern developing
of some kind of broad cancer preventive effect from vitamin E," said
Dr. Demetrius Albanes, a National Cancer Institute researcher and co-author
of the study.
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- A report on the study will be published
Wednesday in the Journal of the National Cancer Institute.
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- Albanes said that although both vitamin
E and beta carotene, the form of vitamin A used in the study, are antioxidants,
only vitamin E appears to give a statistically significant protection against
cancer.
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- In fact, said Albanes, the data suggest
that beta carotene users in the study were about 16 percent more likely
to develop lung cancer. This result, first reported three years ago, startled
many researchers, who had expected beta carotene to be proved as a cancer
preventive.
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- Albanes said detailed analysis of the
study shows that vitamin E, in the form of alpha tocopherol, provides some
protection against colorectal cancer and lung cancer, although these data
are not as dramatic as the prostate cancer results.
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- "This is a striking one-third reduction
in the incidence of prostate cancer and an even more impressive reduction
in the rate of prostate cancer deaths," said Albanes, who participated
with researchers from the University of Helsinki, Finland, in the study.
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- Dr. Ishwarlal Jialal, a researcher at
the University of Texas, Southwestern Medical Center, in Dallas, said the
study "is a very significant observation" on the anticancer effects
of vitamin E.
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- However, he said, "it needs to be
confirmed by another group study, especially among nonsmokers."
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- Jialal said his earlier research has
shown that vitamin E helps reduce heart disease and has other benefits.
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- The Finnish study involved 29,133 male
smokers, ages 50 to 69, who had been selected to take part in a lung cancer
study evaluating the effect of beta carotene and vitamin E on smokers.
The men were divided into four groups. One group took beta carotene supplements;
another took vitamin E; a third took a combination of the two, while the
last group took only a placebo.
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- The vitamin E dosage was 50 mg a day,
which is the equivalent of 50 international units. This is about five times
the recommended minimum daily intake for men, said Albanes, and about 2
1/2 times what most people get from food.
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- After five to eight years on the supplements,
Albanes said, the 14,564 men taking vitamin E alone or with beta carotene
had 32 percent fewer cases of prostate cancer than the 14,569 who did not
take vitamin E.
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- Additionally, there were 41 percent fewer
prostate cancer deaths among men taking vitamin E, the researcher said.
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- Taking the vitamin E supplement, however,
was not risk-free, said Albanes. Among those taking the vitamin, there
were 66 deaths from the cerebral hemorrhage, or bleeding, type of stroke,
compared with 44 such deaths among the men not taking vitamin E.
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- "This is one of the potential downsides
that was observed," said Albanes. "Vitamin E is known to have
some effect on blood clotting."
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- Although the finding for vitamin E is
encouraging, he said it is premature to recommend that everybody start
taking vitamin E supplements. Albanes said there needs to be another long-term
study involving nonsmokers and people of different races and ethnic backgrounds.
The Finns in the study, he said, were all smokers and all white men.
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- Foods rich in vitamin E include vegetable
oils, particularly those from safflower, sunflower and cotton seeds; wheat
germ and whole grains; and whole nuts, such as almonds.
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- But to get 50 IU of vitamin E from such
foods, he said, would mean taking in a great deal of extra dietary fat,
which may not be beneficial.
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