People, including researchers, hold markedly different beliefs about vitamin E supplements, ranging from "protective" to "useless" to "harmful." Some doctors take vitamin E, but dont recommend it for their patients. Some do the reverse. Some experts think there have been too many vitamin E studies and say its time to quit expecting health benefits. Others say nearly all the research has been flawed and recommend starting afresh using even higher doses of vitamin E or different forms of it.
The supplements industry has, of course, continued to urge people to take vitamin E supplements.
Early studies (mostly observational and not always well-designed) found a benefit, especially for preventing heart disease, while later studies (many of them well-designed clinical trials) have not. Indeed, a few recent studies suggested that vitamin E supplements might actually be harmful. But a 2007 study found that the now-discredited claims for vitamin E persist widely on the Internet and elsewhere, and that even many scientists continue to believe them.
Heres a summary of the latest news:
Cardiovascular disease: Its logical that vitamin E might help prevent heart disease because of its antioxidant properties (free radicals are believed to be a factor in atherosclerosis), but supplements have not proved helpful. And many experts now have questions about the theory that antioxidants can prevent heart disease. In November the Physicians Health Study II produced the latest negative results: Among more than 14,000 male doctors taking high doses of vitamin C or E for eight years, neither supplement reduced heart attacks, strokes, or cardiovascular deaths. In fact, vitamin E slightly increased the risk of hemorrhagic (bleeding) strokes.
Longevity and/or potential harm: According to a 2008 review of studies that included almost half a million people, antioxidant supplements (including vitamin E, beta carotene, vitamin C, and selenium) did not prolong life or protect against disease. This review was done by the Cochrane Collaboration, an independent group that evaluates evidence. Some studies suggested benefit, others harmbut the best were largely neutral.
Other large reviews have also suggested that vitamin E supplements and other antioxidant pills dont help and may hurt. One such study, in the Journal of the American Medical Association in 2007, pointed to a slight increase in mortality for those taking antioxidant supplements, including vitamin E.
Lung cancer: Vitamin supplements, including vitamin E, have not proved protective, according to a 2007 study funded by the National Cancer Institute (NCI). Smokers who took E supplements actually had a slightly higher risk of lung cancer. Though this is not the final word, the researchers warned smokers that the supplements "may be detrimental."
Prostate cancer: While some early studies suggested a protective effect, more recent research has not. In October 2008 researchers halted a major clinical trial (also funded by the NCI) on vitamin E and prostate cancer after five years because they said there was no benefit. Apparently, there were slightly more cancers among the E takers, though this may have been due to chance; the men will continue to be monitored to see if this risk is real.
Alzheimer's disease: There is little good evidence that E supplements can prevent or treat either cognitive impairment or Alzheimer's, according to another Cochrane review in 2008. In-deed, only two studies were found worthy of review. One was a clinical trial of people with moderate to severe Alzheimers: vitamin E supplements may have slightly decreased disease progression, but, surprisingly, the patients experienced more falls. The other looked at mildly impaired people, in whom large doses of E (2,000 IU daily) produced no benefit.
Macular degeneration, the major cause of blindness in older people: Research about vitamin E has been inconclusive. Nevertheless, vitamin E is one ingredient in the special formulations (PreserVision and similar supplements) that have been shown to slow the progression of the disease.