The Vitamin E Family
Vitamin E is a family of 8 compounds: four tocopherols and four tocotrienols. Each of the four tocopherols and tocotrienols are named after the four letters of the greek alphabet: alpha, beta, gamma, delta.
The chemical difference between the tocopherols is the position of the methyl groups on the chroman ring.
The chemical difference between the tocotrienols and the tocopherols is the double bonds on the tail. The chemical difference between the tocotrienols, like the tocopherols, is the position of the methyl groups on the chroman ring. The active component of the tocopherols and tocotrienols is the hydroxyl group on the chroman ring.
What is the significance of the different members? The eight members of the vitamin E family have some functions that are similar to the others and other functions that are completely different. These members also are present in different areas of the body in various amounts. For example, there is more gamma-tocopherol than alpha-tocopherol in the skin.
Why was alpha-tocopherol synonymous with Vitamin E? Mention vitamin E and many people in the food and nutrition business will still think of alpha-tocopherol. First, it is present in the human body in the highest level of all members. Second, it is by far the most effective of the eight in the classical vitamin E assay for what we thought was its main function - to support reproduction.
It is only recently that scientists have been reminded that there is more to vitamin E, seven more members that have long been ignored. Strong scientific research indicates that the long ignored members have important functions, some of which are different from those of alpha-tocopherol.