Vitamin E

Vitamin E is a group of eight fat-soluble compounds that include four tocopherols and four tocotrienols. Vitamin E is fat-soluble, so dietary supplement products are usually in the form of the vitamin, esterified with acetic acid to generate tocopheryl acetate, and dissolved in vegetable oil in a soft gel capsule. For alpha-tocopherol, amounts range from 100 to 1000 IU per serving. Smaller amounts are incorporated into multi-vitamin/mineral tablets. Gamma-tocopherol and tocotrienol supplements are also available from dietary supplement companies. The latter are extracts from palm or annatto oils.

Vitamin E may have various roles as a vitamin. Many biological functions have been postulated, including a role as a fat-soluble antioxidant. Vitamin E is also incorporated into cell membranes, which are therefore protected from oxidative damage. Vitamin E affects gene expression and is an enzyme activity regulator, such as for protein kinase C (PKC) – which plays a role in smooth muscle growth – with vitamin E participating in the deactivation of PKC to inhibit smooth muscle growth.