Vitamin E is one of the body’s most important antioxidant nutrients. Antioxidants protect healthy cells from oxidative and free radical damage. Free radicals are unstable chemicals formed in the body during metabolism and from exposure to environmental sources. Free radicals are necessary for energy metabolism and immune function, but when an excessive number of free radicals are formed, they can attack healthy cells, especially cell membrane lipids and proteins. Vitamin E is an especially valuable antioxidant in the cell membranes, where it prevents oxidation of unsaturated fatty acids by trapping free radicals. This helps stabilize and protect cell membranes, especially red blood cells and tissues sensitive to oxidation, such as the lungs, eyes, and arteries.† Vitamin E also supports the liver and other physiological processes.† Related to its antioxidant properties, vitamin E is important for normal immune function, and many studies show that it prevents lipid peroxidation of blood lipoproteins, such as LDL-cholesterol.
While many think that the term "vitamin E" refers to a single entity, it actually describes a family of eight different compounds known as, tocopherols and tocotrienols. Both the tocopherols and tocotrienols are further divided into their alpha, beta, gamma and delta isomers. These two groups of compounds are similar with respect to their structure, but do have subtle molecular structure differences.