Vitamin E, Polarised light micrograph of crystals of alpha-tocopherol succinate. This is the most effective of the Vitamin E group, which contains methylated tocopherols and tocotrienols. The alpha form is properly known as 5,7,8-trimethyltocol. The succinate is a tocopherol ester, used in dietary supplements. Vitamin E is widely distributed in vegetable lipids and the body fat in animals. It protects unsaturated fat from oxidation, and is thus thought to stabilise cell membranes. Vitamin E deficiency is rare, as the dietary supply of Vitamin E group chemicals is nprmally ample and it has a long residence time in the body. Magnification x10 at 35mm size.