Vitamin E is a fat-soluble vitamin. Its main function - as a powerful antioxidant - is to protect body tissues from damage caused by free radicals. The body also needs vitamin E to help keep the immune system strong against viruses and bacteria. Vitamin E is also important for the formation of red blood cells and helps the body utilize vitamin K. It helps to dilate blood vessels and prevent blood clotting (clot formation) inside them. Cells use vitamin E to interact with each other and perform many important functions