Over the past decade, vitamin E has become one of the top-selling supplements in the United States, in part because research released in the early- to mid-1990s suggested that taking vitamin E supplements might protect against heart disease, boost the immune system and reduce the risk of macular degeneration.
Now, however, more recent studies have failed to confirm these earlier findings, calling into question vitamin E's status as a super supplement.
Found naturally in vegetable oils, nuts, seeds, and green, leafy vegetables, vitamin E works as an antioxidant in the body, preventing and repairing damage caused by free radicals. Damage to body cells by free radicals may contribute to the development of several chronic diseases including heart disease, cancer, diabetes and age-related macular degeneration.
Evidence from preliminary studies suggested that taking vitamin E supplements provided protection from certain diseases associated with free radical damage, particularly heart disease.
However, subsequent studies have repeatedly failed to support these findings. When researchers at the Cleveland Clinic Foundation reviewed seven vitamin E studies involving more than 80,000 participants who took between 50 and 800 International Units of vitamin E daily and were followed for up to six years, no dose of vitamin E was proven to be beneficial for reducing death from cardiovascular disease. Further, a Canadian study that tracked approximately 2,500 women and 7,000 men aged 50 years or older who were given either a vitamin E supplement or a placebo found that, after five years, those taking the vitamin were no better off than those taking a placebo. In fact, supplement-takers suffered as many heart attacks, strokes and deaths from cardiovascular disease as did placebo-takers.
Vitamin E supplements also recently failed to demonstrate that they could boost immunity in older people. Researchers in the Netherlands randomly assigned 652 healthy people aged 60 or older to take a vitamin E supplement, a placebo or a multi-vitamin for 15 months. Interestingly, when people receiving the vitamin E supplement got a cold or the flu, it lasted an average of five days longer and they suffered more symptoms than the placebo-takers. In addition, a 2002 Australian study of 1,000 healthy volunteers found that those who took vitamin E supplements were no less likely to be diagnosed with macular degeneration than those who took a placebo.
Despite the fact that vitamin E supplements have not lived up to all of their expectations, scientists have not lost hope. In a study conducted at four institutions in the United States, elderly people given a combination of vitamin E and vitamin C supplements had significantly lower occurrences of Alzheimer's diseases than those who received no supplementation. Still other studies have indicated that vitamin E may play a role in delaying the onset of Alzheimer's symptoms. Additionally, vitamin E is being investigated as to whether it may help prevent prostate cancer. However, most of the promising evidence is from studies conducted with smokers, so it is too early to tell if similar effects will be seen in non-smokers.
As scientists continue to examine vitamin E and its potential health benefits in supplemental form, one thing remains true. Foods rich in vitamin E, like nuts, seeds and green leafy vegetables, tend to be important sources of other complementary nutrients as well.
Including foods rich in vitamin E in your daily meals will always be good advice. As for vitamin E supplements, it's best to consult your health-care provider before consuming high doses of vitamin E.