The form of vitamin E called alpha-tocopherol is healthier than other forms of vitamin E, according to the National Institutes of Health Office of Dietary Supplements. It is the only one of the eight forms of vitamin E effectively used by the body. The liver releases alpha-tocopherol but causes the body to excrete the other forms of the vitamin.
Vitamin E is a fat-soluble antioxidant that protects the body from damage by free radical oxygen molecules that damage cells by stealing electrons from them, states the Office of Dietary Supplements. Vitamin E also supports the immune system, although its effectiveness when it comes to preventing such diseases as cancer, cataracts, cardiovascular disease and diabetes is uncertain, explains WebMD. It is unusual for healthy people to be deficient in vitamin E, which is readily found in green, leafy vegetables; eggs; nuts; and vegetable oils.
The risks of taking large amounts of vitamin E over the long term are also uncertain, according to WebMD, though it seems to increase the risk of stroke. An overdose of vitamin E can lead to nausea, vomiting and kidney failure. Because too much vitamin E can increase the risk of bleeding, it should not be taken by people who are also taking anticoagulants.