Body and Being
NATURAL SOLUTIONS FOR HEALTH AND BODY CARE
Monthly articles are supplied by guest writers who explore natural solutions to health and well-being issues.
Taking a closer look at vitamin E
(January 2005)
What is vitamin E?
Vitamin E is a fat-soluble vitamin that exists in eight different forms. Each form has its own biological activity, which is the measure of potency or functional use in the body. Alpha-tocopherol is the name of the most active form of vitamin E in humans. It is also a powerful biological antioxidant.
Vitamin E in supplements is usually sold as alpha-tocopheryl acetate, a form that protects its ability to function as an antioxidant. The synthetic form is labeled "D, L" while the natural form is labeled "D". The synthetic form is only half as active as the natural form.
Antioxidants such as vitamin E act to protect your cells against the effects of free radicals, which are potentially damaging by-products of energy metabolism. Free radicals can damage cells and may contribute to the development of cardiovascular disease and cancer.
Studies are underway to determine whether vitamin E, through its ability to limit production of free radicals, might help prevent or delay the development of those chronic diseases. Vitamin E has also been shown to play a role in immune function, in DNA repair, and other metabolic processes.
What is the health risk of too much vitamin E?
The general health risk of too much vitamin E is low. Although evidence indicates that taking a vitamin E supplement containing 530 mg or 800 IU daily for four months is not toxic, the long-term safety of vitamin E supplementation has not been tested.
The Institute of Medicine has set an upper tolerable intake level for vitamin E at 1,000 mg (1,500 IU) for any form of supplementary alpha-tocopherol per day. Upper tolerable intake levels represent the maximum intake of a nutrient that is likely to pose no risk of adverse health effects in almost all healthy individuals in the general population.
Vitamin E supplementation and all-cause mortality
A recent meta-analysis that combined the results of 19 clinical trials of vitamin E supplementation for various diseases, including heart disease, end-stage renal failure and Alzheimer’s disease, reported that adults who took supplements of 400 IU/day or more were 6 percent more likely to die from any cause than those who did not take vitamin E supplements.
However, further breakdown of the risk by vitamin E dose and adjustment for other vitamin and mineral supplements revealed that the increased risk of death was statistically significant only at a dose of 2,000 IU/day, which is higher than the UL (upper limit, or upper tolerable intake level) for adults.
Furthermore, three other meta-analyses that combined the results of randomized controlled trials designed to evaluate the efficacy of vitamin E supplementation for the prevention or treatment of cardiovascular disease found no evidence that vitamin E supplementation up to 800 IU/day significantly increased or decreased cardiovascular disease mortality or all-cause mortality.
At present, there is no convincing evidence that vitamin E supplementation up to 800 IU/day increases the risk of death from cardiovascular disease or other causes.
Sources: Excerpted from Vitamin E fact sheet, National Institutes of Health, Office of Dietary Supplements. References and full text available at http://ods.od.nih.gov/factsheets/vitamine.asp and the Web site of The Linus Pauling Institute at Oregon State University http://lpi.oregonstate.edu/infocenter/
vitamins/vitaminE/index.html#mortality
This information is intended for educational purposes only. It is not provided in order to diagnose, cure, mitigate or prevent any disease, illness or injury. Those individuals suffering from any disease, illness or injury should consult with their healthcare provider.
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