It has long been hoped that vitamin E, because of its antioxidant ability, could help prevent or treat Alzheimer’s disease and other forms of dementia. But studies on the vitamin as a treatment for Alzheimer’s have had mixed results, and research on the vitamin’s effect in people with mild cognitive impairment has found that the vitamin does not slow the progression to dementia. The latest twist in the story comes from a large, well-designed study published in the Journal of the American Medical Association, which found benefits in people with Alzheimer’s who took vitamin E—though not all of the benefits that were hoped for.
The study involved 613 veterans (almost all men) with mild to moderate Alzheimer’s who were all taking cholinesterase inhibitors (a class of drugs for dementia), such as donepezil (Aricept). They were divided into four groups: high-dose vitamin E (2,000 IU of synthetic E a day, nearly 90 times the recommended daily allowance, or RDA); memantine (another dementia drug, although not a cholinesterase inhibitor); a combination of the vitamin and drug; or a placebo. All groups continued to take their cholinesterase inhibitors. Over the course of a little more than two years, the vitamin E group had slower functional decline (problems with daily activities such as getting dressed and shopping) than the placebo group. Thus they needed less help from caregivers— about two hours less a day, on average.
Those who took memantine showed no functional benefit compared to a placebo, nor, curiously, did those taking the memantine plus vitamin E. Disappointingly, memory and cognitive skills were not affected by any of the interventions.
The very high doses of vitamin E appeared to be safe. That’s reassuring, since some earlier studies have suggested that the vitamin can be harmful and may even increase mortality rates slightly.
There are no good treatments for Alzheimer’s—the approved drugs are of limited value—so anything that may improve the life of those afflicted with it, as well as their caretakers, even modestly, is worth a shot. But such high doses of vitamin E should be used only under medical supervision. It’s not known if a lower dose would have been beneficial, or if natural vitamin E would have performed better. In any case, don’t take vitamin E in hopes of preventing dementia, since there’s no evidence for this.