Vitamin E Update: Gamma-tocopherol, Not Alpha-tocopherol, Inhibits Cancer Cell Growth

Gamma-tocopherol is the most abundant form of Vitamin E. However, research has found that much of it is excreted through urine after being metabolized by the liver. The "gamma" form of Vitamin E has been shown to be superior to the "alpha" form for inhibiting cancer cell growth. Recent research supports the theory that gamma-tocopherol's antioxidant role goes above and beyond that of alpha-tocopherol by effectively entrapping and removing mutagenic (induces genetic mutation) oxidants. It is the gamma-form that seems to disband free radicals and force them into submission.

Cyclooxygenease-2 (COX-2) is an enzyme that causes synthesis of prostaglandin El, an inflammation-causing chemical in the body, which plays a key role in inflammation, vascular heart disease and cancer. It promotes tumor growth via several mechanisms, one of which is to promote the development of blood vessels into the tumor. It is believed that blocking the action of the COX-2 enzyme is a crucial variable in cancer therapy.

A study showed that gamma-tocopherol (gamma T) reduced prostaglandin synthesis in both macrophages (immune cells) and human epithelial cells. In addition, gamma tocopherol’s major metabolite (gamma-CEHC, produced by metabolism), also showed an inhibitory effect. In contrast, the alpha-tocopherol form of Vitamin E only slightly reduced prostaglandin formation in macrophages, and had no effect in epithelial cells. The inhibitory effects shown by Vitamin E gamma-tocopherol and its metabolite came from their inhibition of COX-2 activity, and appeared to be independent of antioxidant activity.

The Vitamin E gamma-tocopherol metabolite also inhibited prostaglandin synthesis to COX-2-preinduced cells after arachidonic acid was added, when exposed for only one hour. However, gamma-tocopherol required eight to 24 hours to cause the inhibition. The results indicate that gamma ­tocopherol and its major metabolite both possess anti-inflammatory activity, important in human disease prevention.

Maximum Vitality contains all the tocopherol and tocotrienol forms of Vitamin E.

Reference

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2000, Vol 97, Iss 21, pp 11494-11499

Key concepts: Vitamin E, alpha-tocopherol, gamma-tocopherol, cancer cell