Fat-Soluble Vitamins; Vitamin E
Vitamin E Vitamin E The vitamin E family consists of to subgroups __the tocopherols and the tocotrienols __each containing four members designated by letters of the Greek alphabet (alpha, beta, gamma, and delta). All consist of a complex ring structure with a long saturated (in tocopherols) or unsaturated (in tocotrienols) side chain. The positions of methyl groups (CH3) on the side chain and their chemical rotations distinguish the four members within each subgroup. Of all the members of the vitamin E family, only alpha-tocopherol is maintained in the body and can meet the body's needs for the vitamin. The others are not converted to alpha-tocopherol in the body, nor are they recognized by its transport protein. For these reasons, the RDA is based only on alpha-tocopherol. Most vitamin E research has focused on alpha-tocopherol, but recent studies suggest that the other tocopherols and tocotrienols have unique antioxidant and anti-inflammatory roles that better protect against ...