The last year hasn't been a good one for vitamin E.
Once determined a wonder supplement, an uncostly and mild pill that might preclude heart disease, cancer and Alzheimer's, a flurry of modern clinical trials suggest it does none of those things.
Vitamine
Some even suggest there is a small occasion it could be harmful in higher doses.
Yet while the oily tiny capsule apparently can't keep habitancy alive longer, it refuses to die, in part because in nearly every one of the modern negative studies some caveat or contradictory seeing creates a glimmer of hope.
It also doesn't hurt that the dietary supplement business continues to promote vitamin E and offers experts to refute some of new research.
"It doesn't go away," said Edgar Miller, a vitamin E researcher and connect professor of medicine at Johns Hopkins University. "Why does it keep selling when there are so many of these negative studies?"
The respond appears to be a mixture of factors, including years of promising laboratory, animal and epidemiological studies; heavy promotion by the dietary supplement industry; and, more recently, contradictory findings within studies showing no comprehensive benefit.
The required daily estimate is 22 Iu (international units). Many modern clinical trials have ranged from 300 Iu to 2,000 Iu.
Recent clinical trials of high-dose vitamin E have led some researchers to think that vitamin E in megadoses may growth the oxidation of Ldl cholesterol, the bad kind.
When cholesterol is oxidated, it contributes to coronary artery disease.
There also is some concern that high amounts of vitamin E may displace other beneficial anti-oxidants from that midpoint person's diet.
Combining studies
Consider these modern studies: In November, a vitamin E bombshell was dropped by Johns Hopkins University researchers at an American Heart relationship meeting.
They pooled 19 clinical trials of vitamin E spirited 136,000 patients.
In 11 of the high-dose trials (400 Iu or more), the risk of dying from any cause increased 4%, compared with habitancy taking placebos.
Prior to that finding, vitamin E had been considered, at worst, harmless.
"People take anti-oxidants because they want to live longer," said Miller, an connect professor of medicine. "What we showed is you don't live longer."
However, the prognosis also suggested that lower doses of vitamin E (less than 150 I.U. A day) were related with about a 2% reduction in deaths.
Researchers acknowledged any potential shortcomings in their study.
For instance, they noted that any of the high-dose trials complicated habitancy with various persisting diseases and may not apply to wholesome individuals.
They also said the small size of any of the trials in the prognosis and inconsistent reporting of condition events prevented a detailed look at the corollary of various doses of the vitamin.
"It's a very flawed analysis," said Julie Buring, a professor of medicine at Harvard medical School who recently presented her own vitamin E research.
She also said the 4% increased risk of death was not "clinically meaningful" and could be a occasion finding.
Women's condition study
On March 7, Buring and other Harvard scientists presented their own vitamin E study at the American College of Cardiology annual meeting.
Once again, the vitamin threw researchers a curve.
Analyzing data from the Women's condition Study, a trial spirited 40,000 women who got whether 600 Iu of vitamin E every other day or a placebo, researchers found that it in case,granted no comprehensive cardiovascular benefit such as reduction in heart attacks or strokes.
However, an prognosis of a subgroup of women over 65 found a 26% reduction in cardiovascular events.
Buring said that although the seeing was "intriguing," it was not supported by old research.
She added that it needs confirmation.
Adding even more confusion, the study found a statistically necessary 24% reduction in cardiovascular deaths among all the vitamin E users.
Buring also questioned that seeing because there was no comprehensive reduction in strokes and heart attacks. She said it was potential that it was due to other cardiovascular causes such as arrhythmias or heart failure, but there was no uncostly biological explanation for that.
"People should look at that further, but it could be chance," she said.
Buring fulfilled, that vitamin E was neither harmful nor beneficial in preventing cardiovascular disease.
A surprise
About a week after the Women's condition Study, other controversial vitamin E seeing was presented.
The study complicated 9,500 habitancy aged 55 and older with vascular disease or diabetes who were followed for an midpoint of seven years.
It found that 400 Iu of vitamin E a day in case,granted no protection against cancer or major vascular events such as heart attacks or strokes.
In addition, the study found a disturbing 13% growth in heart failure cases and 21% growth in heart failure hospitalizations.
That was the first time that vitamin E had been related with an increased risk of heart failure, said lead author Eva Lonn, a professor of medicine at McMaster University in Hamilton, Ontario.
"I am not convinced about the harm," Lonn added.
Indeed, a modern small study of heart failure patients taking a cholesterol-lowering statin drug suggested that vitamin E authentically increased the statin's quality to enhance blood vessel function and lower inflammation.
Lonn and the other researchers said a impart of all heart failure events in large vitamin E clinical trials "is strongly recommended."
Confounding the heart failure seeing was what appeared to be a statistically necessary 28% reduction in lung cancer cases, although in a secondary prognosis of the data the benefit seemed to disappear.
"The numbers are small," Lonn said. "We think it's a occasion finding."
The researchers noted that other larger vitamin E trials showed no lung cancer benefit.
Alzheimer's research
There still is some hope that vitamin E might help preclude Alzheimer's disease, although in May a clinical trial of 769 patients with mild cognitive impairment found it was of no benefit in delaying the progression to Alzheimer's.
In that trial, the patients took a mega dose 2,000 Iu a day for up to three years, agreeing to the findings in the New England Journal of Medicine.
Other vitamin E / Alzheimer's trials are ongoing.
The anti-oxidant vitamin enthusiasm of the 1990s is being tempered by clinical trials, agreeing to a Jama editorial that accompanied the Women's condition Study results.
"These hopes are now confined to modest expectations for exact disorders and there are concerns about adverse effects," the editorial said.
Reviving Vitamin E Studies That Challenge Claims of Wonder Supplement Also Leave Openings
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