June 3, 2008
New findings presented at the American Academy of Neurology 60th Anniversary Annual Meeting in Chicago show that people with Alzheimer's disease who take vitamin E appear to live longer than those who don't take the vitamin, though more research is needed to confirm these findings.
For the study, researchers followed 847 people with Alzheimer's disease for an average of five years. About two-thirds of the group took 1,000 international units of vitamin E twice a day, along with the Alzheimer's drug Aricept. Like the drugs Exelon and Razadyne, Aricept is known as a "cholinesterase inhibitor," a class of drugs that may temporarily slow, but not reverse, the downward progression of Alzheimer's. Less than 10 percent of the group took vitamin E alone, and approximately 15 percent did not take vitamin E.
The study found people who took vitamin E, with or without an Alzheimer's drug, were 26 percent less likely to die than people who didn't take vitamin E.
Many people with Alzheimer's or at risk for the disease take vitamin E to protect the brain from damage, even though the vitamin does not have proven benefit for brain health. Vitamin E is a potent antioxidant, a substance that neutralizes highly reactive oxygen molecules (or free radicals) throughout the body, including the brain.
Although nobody knows what causes Alzheimer's disease, studies show that an excess of free radicals may damage brain cells. Scientists have been studying antioxidants like vitamin E, vitamin C and others to see if they have benefits for people with Alzheimer's or help prevent the onset of the disease.
Earlier research has suggested that vitamin E may delay the progression of moderately severe Alzheimer's disease. "Now, we've been able to show that vitamin E appears to increase the survival time of Alzheimer's patients as well," said study author Valory Pavlik, Ph.D., with Baylor College of Medicine's Alzheimer's Disease and Memory Disorders Center in Houston. "This is particularly important, because recent studies in heart disease patients have questioned whether vitamin E is beneficial for survival."
Indeed, several years ago, researchers at Johns Hopkins found that taking vitamin E at doses over 200 I.U. a day can increase the risk of having a heart attack. The more vitamin E someone took, the greater his or her overall risk of death. The risk was small -- someone taking 400 I.U. of the vitamin a day for five years, for example, faced a 5 percent higher risk of dying. Still, the researchers concluded it should be avoided.
The current study found an opposite effect: that vitamin E actually boosted survival in people with Alzheimer's. In addition, the study found vitamin E plus an Alzheimer's drug may be more beneficial than taking either agent alone. "Our findings show that people who took a cholinesterase inhibitor without vitamin E did not have a survival benefit," said Dr. Pavlik.
More Research Needed
More research needs to be done to determine why this may be the case, and whether vitamin E is safe and effective for survival in people with Alzheimer's or at risk for the disease.
A number of earlier studies have been conducted on the effects of vitamin E and other antioxidants on Alzheimer's disease. A large population study in 2002, for example, suggested that getting plenty of vitamin E from foods or vitamin supplements may protect against mental decline. Other studies have also suggested that a combination of antioxidants, including vitamins E and C and coenzyme Q10, may offer benefit.
Several large studies of vitamin E for the prevention or treatment of Alzheimer's are ongoing. One, the PREADVISE, for "Prevention of Alzheimer's Disease by Vitamin E and Selenium," trial is attempting to determine if the antioxidant effects of vitamin E and selenium can help to prevent memory loss and dementia in older adults. Another study, sponsored by the Department of Veterans Affairs, is asking whether the combination of vitamin E and Namenda (memantine) slows progression of mild to moderate Alzheimer's disease.
In the meantime, people should not start popping huge doses of vitamin E supplements in the hopes that it will prevent or delay the progression of Alzheimer's. Discuss vitamin E with your doctor. Vitamin E is a fat-soluble vitamin, meaning that it is stored in the body, and might potentially build up to toxic levels or affect the body's breakdown of other medications people may be taking. People who are taking blood thinners or aspirin or who are undergoing surgery might need to take special precaution, as vitamin E may further thin the blood. Tell your doctor what supplement you are taking or wish to take.
Individual vitamin E supplements are commonly sold in strengths of 400 I.U. or 1,000 I.U. A multivitamin supplement contains much less vitamin E, typically 30 to 60 I.U.
In addition to vitamin E supplements, some vegetable oils, nuts, wheat germ and green leafy vegetables and asparagus supply about 10 I.U. of vitamin E per serving. Some fortified cereals also contain vitamin E.
Check www.ALZinfo.org, The Alzheimer's Information Site, for regular updates on the outcome of vitamin E and other Alzheimer's studies.
Presented at the American Academy of Neurology 60th Anniversary Annual Meeting in Chicago, April 12 to 19, 2008.