vitamin E

:  any of several fat-soluble vitamins that are chemically tocopherols or tocotrienols whose lack in the human body is associated especially with neurological symptoms (as ataxia and muscle weakness), that are found especially in wheat germ, vegetable oils, egg yolk, and green leafy vegetables or are made synthetically, and that are used chiefly in animal feeds and as antioxidants; especially :  alpha-tocopherol