Vitamin E is a fat-soluble vitamin that acts as an antioxidant. It is an antioxidant that protects body tissue from damage caused by unstable substances called free radicals. Free radicals can harm cells, tissues, and organs. It 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.