Vitamin E may not reduce heart disease risk, new study says
January 20, 2000
Web posted at: 9:33 AM EST (1433 GMT)
By Ulysses Torassa
(WebMD) -- A new study is raising questions about the highly touted ability of vitamin E to fight cardiovascular disease.
While vitamin manufacturers frequently make this claim, a large-scale study published in this week's New England Journal of Medicine found that daily doses of vitamin E did not reduce cardiovascular disease risk in older men and women considered at high risk for problems such as heart attack or stroke.
Cardiovascular disease is the country's number-one killer, and affects an estimated 58 million Americans.
"Everybody has already labeled vitamin E as a preventive for cardiac disease, and at first we thought, 'We're missing something,'" said Jackie Bosch, MSc, coordinator of the study, which was done by the Heart Outcomes Research Evaluation Group, a multi-national consortium of researchers.
Scientists know that vitamin E is an antioxidant that may reduce artery-clogging plaques that restrict blood flow. And previous studies have shown that people who said they ate a lot of vitamin- and antioxidant-rich fruits and vegetables or who took vitamin E supplements had lower incidences of heart disease and stroke.
But the new study is different in that it actually gave patients vitamin E, then tracked the participants' health from the time they began taking the supplements.
During the study, more than 4,700 patients who were considered at high risk for cardiovascular disease took daily 400-international unit (IU) doses of vitamin E. A similarly sized group of high-risk patients took a placebo, or sugar pill. Neither the patients nor the doctors knew who took the placebo and who took the supplements. After four and a half years, both groups had experienced roughly the same number of heart attacks and strokes.
This isn't the first research to cast doubt on the usefulness of vitamin E supplements for preventing heart disease. A study, published in the August 1999 issue of the British journal The Lancet, in which high-risk patients were given 300 IU daily of the vitamin for three and a half years failed to demonstrate any benefits.
Other factors at work
Bosch said it is possible that vitamin E needs more time to work its magic. The group received additional funding from the Natural Source Vitamin E Association to extend the study for two and a half years.
Furthermore, it may be that because patients in the study were at high risk for heart attack and stroke, their conditions were too far advanced to be reversed, Bosch said. Participants in previous studies that showed vitamin E to be beneficial weren't necessarily at high risk.
"All we can say for now after four and a half years of follow-up is that there is no effect on cardiovascular disease," Bosch said. "Potentially, longer-term use could be effective, but that has yet to be proven."
The debate continues
Vitamin E researcher Jeffrey Blumberg, PhD, chief of Tufts University's Antioxidants Research Laboratory, said he was disappointed by the latest findings, but remains a believer in the power of antioxidants. Research presented at the American Heart Association meeting in November suggested that vitamin E combined with vitamin C could help reduce the build-up of arterial plaques.
Antioxidants don't work alone; they work in an antioxidant network, Blumberg said.
However, the study results give the American Heart Association (AHA) all the more reason to stand by its oft-criticized policy of not recommending supplements, including vitamin E, said Ronald Krauss, MD, head of molecular medicine at the Lawrence Berkeley Laboratory and a volunteer AHA spokesman.
"This study, coupled with another recent report from Europe, shows rather conclusively that giving vitamin E as a supplement to patients with heart disease has no apparent benefit after a fair amount of time," Krauss said.
Still, he said it is possible that vitamin E or other antioxidants may be beneficial when delivered in foods. The AHA does recommend a diet high in fruits and vegetables, which contain many antioxidants.
Researchers have also found evidence suggesting that vitamin E supplements may prevent or slow the progress of prostate cancer and Alzheimer's disease and improve immune system function.
The evidence is provocative enough that the Heart Outcomes group, which conducted the study, gathered data for cancer prevention as well. While the current published article hints at some possible benefits, the complete results will be published later, Bosch said.
Copyright 2000 Healtheon/WebMD. All rights reserved.
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