Gamma-tocopherol in stroke prevention
MELBOURNE, AUSTRALIA. Natural vitamin E is not a single compound but a complex of at least four tocopherols (alpha, beta, delta, and gamma) and four tocotrienols (alpha, beta, delta, and gamma). Alpha-tocopherol is the predominant form found in human blood, while gamma-tocopherol is the predominant form found in food. Based on the finding that alpha-tocopherol is the most abundant form in blood, scientists concluded that it was also the most active and beneficial form. This led to the formulation of vitamin supplements based solely on alpha-tocopherol, and later to the synthesis and marketing of synthetic (dl-) alpha-tocopheryl acetate. Dl-alpha-tocopheryl acetate also quickly became the preferred form used in clinical trials aimed at evaluating the benefits of vitamin E, particularly in regard to cardiovascular disease.

A team of Australian and Chinese researchers now suggests that gamma-tocopherol may be significantly more effective than alpha-tocopherol and may be particularly beneficial in stroke prevention. Their clinical trial included 39 healthy volunteers (19 men and 20 women) between the ages of 20 and 40 years. The participants were randomly assigned to supplement with a placebo, or 100 mg/day or 200 mg/day of pure gamma-tocopherol. Blood samples were drawn for analysis at the beginning and end of the 5-week trial. Supplementation clearly increased gamma-tocopherol concentrations in blood serum from 5.3 to 16.8 mg/mL in the case of the 100-mg/day dose, and from 5.4 to 30.1 mg/mL in the case of the 200-mg/day dose. The serum concentration of alpha-tocopherol did not change significantly during the trial.

The researchers also noted a significant decrease in platelet activation, LDL cholesterol level, platelet aggregation, and mean platelet volume. They also made the following interesting observations:

  • "Several independent investigations have demonstrated that the blood concentration of gamma-tocopherol, not alpha- tocopherol, was negatively correlated to the incidence of coronary heart disease."
  • "Supplementation with large amounts of alpha-tocopherol was shown to increase the breakdown and decrease blood concentrations of gamma-tocopherol."
  • Both natural and synthetic alpha-tocopherol suppresses serum gamma-tocopherol. The resulting imbalance between alpha- and gamma-tocopherol may have significant health consequences.
The researchers conclude that the results of their study suggest, "that the daily consumption of small amounts of gamma-tocopherol, in conjunction with usual dietary intake from mixed food sources may provide protection from oxidative damage and prevent thrombosis."

Singh, I, et al. Effects of gamma-tocopherol supplementation on thrombotic risk factors. Asia Pacific Journal of Clinical Nutrition, Vol. 16, No. 3, 2007, pp. 422-28

Editor's comment: The results of this study support my own long-held belief that supplements, especially vitamins and antioxidants, should always be taken in a formulation that mimics, as close as possible, the way the vitamin/antioxidant is found in nature. Thus, vitamin C should always be taken with the bioflavonoids with which it is associated in nature. B vitamins should always be taken as the whole complex, as should vitamin E with emphasis on natural gamma-tocopherol. The finding that gamma-tocopherol helps prevent thrombosis logically leads to the conclusion that it may also be effective in preventing transient ischemic attacks (TIAs) and ischemic stroke.