Vitamin E proved to be a bust for preventing heart disease
and cancer in a widely publicized study in women, but intriguing results from
the same trial suggest a role for the vitamin in reducing the risk of
life-threatening blood clots.
Researchers warn that the findings must be confirmed, and they say no one
taking prescription blood thinners to prevent deep vein blood clots should stop
But Harvard Medical School professor of medicine Robert J. Glynn, PhD, says
vitamin E shows promise for preventing the potentially deadly clots in
high-risk patients who aren't on prescription blood thinners like warfarin.
"Warfarin is very effective, but it has a lot of side effects and people
must be monitored closely when they are on it," Glynn tells WebMD.
Vitamin E and Deep Vein Clots
Clots that form in the arteries lead to heart attacks and strokes, but deep
vein clots become deadly when they break off and travel to the lungs, causing
pulmonary embolisms. Deep vein clots and pulmonary embolism from blood clots
are known collectively as venous thromboembolism (VTE).
That is what happened to NBC reporter David Bloom, who died in 2003 after
spending days in a cramped military vehicle while covering the invasion of
Spending long periods in a confined space without moving greatly increases a
person's risk for developing deep vein blood clots, as do obesity, pregnancy,
advanced age, oral contraceptives, and hormone therapy.
The American Heart Association (AHA) estimates that about 200,000 new cases
of VTE occur in the U.S. each year, with 30% of cases resulting in death within
30 days. Another 30% of people develop new clots within 10 years.
In the newly published study, Glynn and colleagues reviewed data from the
Women's Health Study, which included just under 40,000 women aged 45 and older
who took either 600 international units (IU) of vitamin E or a placebo every
other day and were followed for an average of 10 years.
During the trial, 213 women in the vitamin E group and 269 women in the
placebo group developed venous thromboembolism.
Overall, women who took vitamin E were 21% less likely to develop venous
thromboembolism than women who did not, but the reduction was more than double
this (44%) among the women who had a history of clots.
And taking vitamin E appeared to cut the clot risk in half among women with
genetic mutations that increased their risk.
The study appears in the Sept. 25 issue of the AHA journal
"The puzzle fits together in a way that is really interesting,
suggesting a possible benefit in precisely the people who need it most,"
Vitamin E 'Not Ready for Prime Time'
The American Heart Association does not recommend antioxidant vitamins like
vitamin E, C, and beta-carotene for preventing heart attacks and strokes, and a
2004 analysis of 14 studies suggested that taking 400 IU of vitamin E a day or
more increased the risk of death.
But Glynn says no significant side effects were seen among women in the
study who took vitamin E for an average of 10 years.
He says more study is needed to confirm the findings, and New York
University cardiologist Nieca Goldberg, MD, agrees.
Goldberg directs NYU's women's heart program and is a spokeswoman for the
"This is very interesting, but it isn't necessarily ready for prime
time," she tells WebMD. "People on strong blood thinners like warfarin
should absolutely stay on them, and anyone else who might consider taking
vitamin E for this reason should discuss it with their doctor first."
By Salynn Boyles
Reviewed by Louise Chang
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