Vitamin E is an antioxidant that protects body tissue from damage caused by unstable substances called free radicals. Free radicals can harm cells, tissues, and organs. They are believed to play a role in certain conditions associated with aging. Vitamin E is also important in the formation of red blood cells and helps the body to use vitamin K. The ability of vitamin E to prevent cancer, heart disease, dementia, liver disease, and stroke are still not known. At lower levels, vitamin E may help protect the heart. The best way to get enough essential vitamins is to eat a balanced diet that contains a variety of foods.