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New Study Finds Vitamin E,
Beta-Carotene Ineffective
Millions taking popular antioxidants in the hope
of preventing heart disease may be putting themselves at risk.
A new analysis published in The Lancet medical journal
today found vitamin E and beta-carotene are ineffective in protecting
against heart disease and other causes of death.
The research, carried out at the Cleveland Clinic, also found
that such supplements could be harmful to certain people, supporting
previous criticism in the medical community of the widespread
use of antioxidant pills.
"I have been surprised how difficult it has been for patients
to give [antioxidant vitamins] up," says Dr. Lori Mosca, director
of the preventive cardiology unit of New York Presbyterian Hospital.
"This study adds to the growing body of data that [not only is
there no] benefit but potential harm with antioxidant vitamins."
Early Warning Signs
Dr. B. Greg Brown, professor of cardiology at the University
of Washington in Seattle, pointed to trials several years ago
that he said should have served as an early warning sign.
"About 1995, large randomized trials appeared which showed no
benefit [to taking these vitamins] and, in fact, small adverse
trends. But by that time, the hypothetical benefit was now 'fact'
in the minds of the physicians and their patients, who continued
vitamin use despite the real facts.
There are many patients
that continue, with blind faith, to take antioxidant vitamins
to prevent heart disease or cancer," Brown said.
The Cleveland Clinic team's analysis of 12 previous clinical
trials investigating the effects of vitamin E and beta-carotene
did not find that these supplements increased cardiovascular or
overall health. It found that beta-carotene supplements slightly
increased the odds of death, mainly among smokers who were at
risk of lung cancer.
Earlier studies had shown a significant benefit to taking antioxidants
such as vitamin E and beta-carotene, fueling the natural supplement
craze that continues to sweep the nation.
Dr. Mark Ebell, professor at Michigan State University and editor
of American Family Physician, noted: "I bet if you ask
patients, 90 percent of those who have an opinion think [taking
antioxidant supplements] helps. Many physicians think it helps
as well.
For example, I had a patient yesterday whose
cardiologist had just told him to take vitamin E. I told him it
wasn't necessary, but since the cardiologist is the 'expert' I'm
not sure he'll believe me."
Vitamin E Widely Recommended, But Why?
A 2001 survey by the Council for Responsible Nutrition found
that 75 percent of cardiologists recommend vitamin E to their
patients.
Dr. Richard Roberts, professor of family medicine at the University
of Wisconsin medical school, estimated that about 15 percent of
his adult patients took vitamin E for heart disease prevention.
"The vast majority take 400 IU daily, which is unlikely to do
them much harm,
[though] it's not likely to do them much
good either," Roberts said.
Nineteen percent of American adults regularly take a vitamin
E supplement, according to a recent survey by the Hartman Group.
Where Past Studies Went Wrong
Researchers believe that the previous studies showing benefits
to taking antioxidant supplements might have failed to account
for the other nutrients in antioxidant rich foods such as broccoli,
carrots and peaches.
Another possibility is that the respective studies do not distinguish
between primary and secondary prevention. The results of this
particular paper focus on secondary prevention, or helping patients
that already exhibit symptoms of disease, whereas previous reports
have examined the effects of antioxidants on healthy patients.
Still, physicians generally agree that the benefits of taking
vitamin E for adult patients are likely very small.
In light of this and other recent studies calling into question
the efficacy of antioxidant supplements, many physicians are now
following the example of Brown, who said: "One of the adverse
aspects of antioxidants, aside from their small detrimental effects,
is that they provide a diversion away from proven therapies for
these conditions.
My clinical policy is to tell my patients
that antioxidant vitamins are of no proven value against heart
disease or cancer."
Reference
Source 104
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