Updated, 6:17 p.m. |
Does vitamin E help people with Alzheimer's disease? For years, scientists have been trying to find out, guessing that the vitamin's antioxidant properties might be beneficial. But the results from clinical trials have been mixed and — following a report that high doses of vitamin E may increase the risk of death — cautionary.
Now a study suggests that vitamin E supplements may be good for some Alzheimer's patients after all. The benefit was not huge, but for a devastating disease that has proved almost impervious to treatment, it was notable.
The study, published in Wednesday's issue of JAMA, The Journal of the American Medical Association, found that over a little more than two years, high-dose vitamin E slowed the decline of people with mild to moderate Alzheimer's by about six months on average.
Vitamin E did not delay cognitive or memory deterioration, however. Instead, it seemed to temporarily protect something many patients consider especially valuable: their ability to perform daily activities like putting on clothes and feeding themselves.
Compared with other study participants, people who took vitamin E also required about two fewer hours of help from caregivers per day, the researchers said.
"Is it really going to dramatically alter the lives of Alzheimer's patients? That's unclear," said Dr. Scott Small, director of Columbia University's Alzheimer's Disease Research Center, who was not involved in the study. "But it might improve patients' ability to bathe themselves and dress themselves."
Notably, in this study, high-dose vitamin E appeared safe. Many doctors had stopped suggesting it to Alzheimer's patients after a 2005 analysis suggested that high doses could increase the risk of mortality. That analysis looked at vitamin E's effect on patients with various diseases, not just Alzheimer's.
"We were concerned about safety, and we didn't find a safety problem," said Dr. Maurice Dysken, a professor of psychiatry at the University of Minnesota, who led the new study.
Still, experts, including the authors, said the new study did not mean that high-dose vitamin E should be taken by everyone with dementia or everyone hoping to prevent it. The study found benefit only in people with mild to moderate Alzheimer's, a result that echoes research in 1997 showing that vitamin E could delay functional decline for about seven months in people with moderately severe Alzheimer's.
But other studies have found that vitamin E failed to delay dementia in people without symptoms or with mild cognitive impairment, which may precede Alzheimer's.
"It was dead stone cold in the M.C.I. trial," said the leader of that study, Dr. Ronald Petersen, director of the Mayo Clinic's Alzheimer's center. "You couldn't have found a closer match to placebo."
Dr. Denis Evans, a professor of internal medicine at Rush University, who wrote an editorial accompanying the new study, cautioned against extrapolating the results to anyone without mild to moderate Alzheimer's.
"Does this mean that all of us who don't want to develop Alzheimer's should rush out and purchase a bottle of vitamin E?" he said. "Oh, please don't."
The study involved 613 veterans, mostly men, from 14 Department of Veterans Affairs hospitals around the country. The veterans were already taking drugs like Aricept for mild to moderate Alzheimer's. One group received 2,000 I.U.'s of vitamin E daily, much higher than the amount available in a typical supplement. Other groups received memantine (a dementia drug used in medications like Namenda), vitamin E plus memantine or a placebo.
"What we hoped was that memantine would have benefit, vitamin E would have benefit, and combined it would have double the effect," Dr. Dysken said. That did not happen.
Only vitamin E showed a statistically significant effect. Memantine was no better than the placebo at preventing decline, and, inexplicably, the combination of memantine and vitamin E did not work either.
There were other confusing results. While vitamin E helped people retain their ability to perform daily functions longer, it did not significantly slow their cognitive decline, the defining feature of Alzheimer's.
"That they found differences in functional measures and not the cognitive measure gives you pause," Dr. Petersen said.
Some studies have focused more on measures of function than on cognitive scores because the ability to maintain daily routines can matter more to patients and their families. Functional abilities decline for a wide variety of reasons related to aging, not necessarily to Alzheimer's, noted Dr. Evans. Most experts say a truly effective Alzheimer's treatment will improve both function and cognition.
The new study also underscores the complexity of Alzheimer's. Experts could not explain why vitamin E would work in fully developed Alzheimer's, for example, but not earlier. In many conditions, treatments ease symptoms at the early stages but lose effectiveness as diseases strengthen.
Dr. Evans and others said doctors should now consider discussing vitamin E supplements with patients with mild to moderate Alzheimer's disease. But, Dr. Evans said, "2,000 I.U.'s is a lot, and I wouldn't recommend it unless there's some oversight" by a doctor.
Dr. Small said that while he would not "twist the patient's arm to take vitamin E, in the absence of anything else that's dramatic, I would certainly raise this with patients."
Dr. Petersen said he might mention it after trying the other treatments he recommends.
"It's not a slam-dunk; it's not a home run," he said. "It does give some credence to the notion that high-dose vitamin E might be doing something. It gives doctors and patients another option to use as the disease progresses."
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