BERKLEY, CALIFORNIA. Gamma-tocopherol is the most common form of vitamin E in the diet and constitutes 30-50 per cent of total vitamin E levels in human skin, muscle, and adipose (fat) tissue. Alpha- tocopherol, on the other hand, is much less common in the diet, but is the main and, in many cases, the only component of vitamin-E supplements. Dr. Bruce Ames and his colleagues at the University of California now report that gamma-tocopherol may be significantly more effective in combating cancer, heart disease, and neurodegenerative disease than is alpha-tocopherol. Experimenting on human macrophages (scavenger cells) and cells from human lung tissue (epithelial cells) they found that gamma-tocopherol is at least three times more effective in inhibiting the synthesis of prostaglandin E2 (PGE2) than is alpha- tocopherol. As a matter of fact, alpha-tocopherol showed no inhibiting effects in epithelial cells at all. PGE2 plays a key role in promoting inflammation and its associated diseases such as cancer and cardiovascular disease. These findings, combined with recent evidence that blood plasma concentrations of gamma- tocopherol, but not alpha-tocopherol, are inversely correlated with the incidence of heart disease, prompt the researchers to speculate that gamma-tocopherol may actually be more important in disease prevention than is alpha-tocopherol. They conclude "It may be that the inclusion of both alpha- and gamma-tocopherols in vitamin E supplements is more effective in human disease prevention, especially considering that alpha- tocopherol supplementation depresses gamma-tocopherol in human plasma and adipose tissue." [55 references]
Jiang, Qing, et al. Gamma-tocopherol and its major metabolite, in contrast to alpha-tocopherol, inhibit cyclooxygenase activity in macrophages and epithelial cells. Proceedings of the National Academy of Sciences USA, Vol. 97, No. 21, October 10, 2000, pp. 11494-99