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Large doses of vitamin E could be risky
Large doses of vitamin E - widely touted as an elixir of youth - do not
protect against heart attacks and cancer and might actually raise the
risk of heart failure in people with diabetes or clogged arteries, a
study found.
The study, published in Wednesday’s Journal of the American Medical
Association, is just the latest to cast doubt on the safety and
effectiveness of vitamin E supplements and other antioxidants.
The study was designed to examine whether vitamin E pills protect
against heart attacks and cancer. Echoing other recent findings, it
found no benefit against those conditions. But the heart failure finding
was unexpected and should prompt more research to confirm the results,
said Dr. Eva Lonn, a McMaster University cardiology professor who led
the study. Lonn said it is unclear how vitamin E pills might be linked
with heart failure, but she theorized that high doses might disturb the
balance of beneficial, naturally occurring antioxidants.
Vitamin E has been touted in recent decades as a powerful weapon against
aging, capable of protecting against everything from wrinkles to cancer
and dementia. Preliminary research over the past 15 years has suggested
that antioxidants fight the harmful effects of oxygen, warding off
blood-vessel damage and cell abnormalities that can lead to cancer.
About 12 percent of U.S. adults - more than 20 million people - take
vitamin E pills containing the same dose used in the study, and about 40
percent - almost 80 million - use supplements containing some amount of
vitamin E, according to the industry.
Research released last week on nearly 40,000 healthy women showed no
heart benefits from vitamin E pills. And a study reported at an American
Heart Association conference in November found that people taking high
doses were 10 percent more likely to die of any cause than those taking
smaller amounts.
The JAMA study involved 7,030 patients with diabetes or cardiovascular
disease other than heart failure.
Patients 55 and older who took about 400 milligrams of vitamin E every
day for about seven years on average were 13 percent more likely to
develop heart failure than those on dummy pills. Heart failure was
diagnosed in 641 vitamin E patients, compared with 578 patients in the
placebo group.
The dosage was typical of vitamin E pills widely available at health
food stores and pharmacies but well above the recommended 15 milligrams
daily for adults, which can be obtained from food. Lonn said the
findings pertain only to vitamin pills, not a diet containing vitamin
E-rich foods, including nuts and leafy green vegetables. “I don’t think
our study rules out in any way that a balanced diet rich in antioxidants
would actually be beneficial,” she said.—Online |