Vitamin E is the official designation for alpha tocopherol, a fat-soluble nutrient found in the diet in varying amounts. It was first discovered in 1922. The term vitamin E is used to refer to all tocol and trienol derivatives. The tocols are alpha, beta, delta and gamma tocopherols, and the trienols are alpha, beta, delta and gamma tocotrienols. All of these substances have vitamin E activity, and until recently it was thought alpha tocopherol was the most active form. As such, only official vitamin E activity (IU) is given to alpha tocopherol. Recent research however, suggests that gamma tocopherol is as biologically active as alpha tocopherol, and that vitamin E products should contain both tocopherols for maximum benefit.^(2)(3)(4)

As shown in a 1993 study published in the Proceedings of The National Academy of Sciences (Vol. 90, March 1993)⁽¹⁾, gamma tocopherol is superior to alpha tocopherol in the detoxification of nitrogen dioxide (NO₂). Nitrogen dioxide is a highly reactive free radical that has been linked to increased cancer risk in humans. A revealing epidemiologic study on the populations of Fiji and the Cook islands, showed that the serum gamma tocopherol levels in the Fiji population was 2 fold higher than the Cook Islanders, while the Fijian’s lung cancer rate was 10-20 times lower. Both groups had similar alpha tocopherol levels and both groups had similar smoking patterns.⁽¹⁾

Another study in the Proceedings of the National Academy of Sciences (Vol. 94, April 1997) suggests that it could be dangerous to take high doses of vitamin E (alpha tocopherol) without also consuming gamma tocopherol. The study showed that high doses of alpha tocopherol on its own displaces gamma tocopherol in tissues.⁽²⁾

Gamma tocopherol is the predominant tocopherol in natural oils, and it is gamma tocopherol that is being re-evaluated for its role in human nutrition and disease prevention. In a more recent study, also published in the Proceedings of the National Academy of Sciences (Vol. 97, October 2000), scientists have shown that gamma tocopherol plays a critical role in the defense against cancer and cardiovascular disease by inhibiting the process of inflammation more effectively than alpha tocopherol.⁽³⁾

Another study, published in the December 20, 2000 issue of the Journal of the National Cancer Institute, showed that increased levels of gamma tocopherol are linked to a statistically significant reduction in the risk of prostate cancer. The authors concluded that, "Protective association with prostate cancer risk were observed when gamma tocopherol concentrations were above the control subject-based median value."⁽⁴⁾ A December 2002 study published in The FASEB Journal found that gamma-tocopherol inhibits proliferation of prostate and colon cancer cells more potently than alpha-tocopherol, providing a cellular mechanism supporting the concept emerging from epidemiological studies that a greater magnitude of risk reduction for prostate and colon cancer may occur if both total vitamin E consumption and the amount of gamma- tocopherol in the diet or supplementation is increased. ⁽⁸⁾

Vitamin E has been shown to interact with some pollutants that are present in the environment and in the diet. The primary atmospheric pollutants, ozone and nitric oxide, are capable of generating free radicals in the body. Gamma tocopherol has been shown to be the most effective tocopherol in neutralizing the harmful effect of ozone and nitric oxide⁽¹⁾⁽²⁾. The main dietary pollutants, nitrosamines, are amongst the most potent cancer causing agents in man. Alpha tocopherol, along with vitamin C reduces the formation of nitrosamines.

Vitamin E, in particular gamma tocopherol, may reduce the lung damage produced by cigarette smoke. Free radicals are generated in the lung by substances that are present in cigarette smoke. These free radicals are responsible for the increasing risk of lung cancer and emphysema. The level of vitamin E in the fluid surrounding lung tissue is six times less amongst smokers compared to non-smokers. Smokers, and those exposed to second hand smoke, need to supplement the diet with both alpha and gamma tocopherols.

In a December 2001 paper published in the American Journal of Clinical Nutrition "Gamma Tocopherol, the major form of vitamin E in the US diet, deserves more attention"⁽⁷⁾, the authors summarize much of the research on the role of gamma tocopherol in preventing human disease, particularily its role in reducing the risk of CVD, cancer, diabeties, and slowing down the aging process.

A January 2003 study done at the Veterans Affairs Medical Centre, Johnson City, TN shows that different isoforms of Vitamin E (tocopherols) may be chemopreventive, and that gamma-tocopherol may be a more powerful chemopeventive than alpha-tocopherol.⁽⁵⁾

The most recent study (March 2003) compared the effects of mixed tocopherols, where gamma tocopherol was the predominant tocopherol, with alpha tocopherol acetate, on platelet aggregation. The study shows that high-gamma mixed tocopherols decreased platelet aggregation significantly whereas alpha tocopherol acetate on its own had little or no effect.⁽⁶⁾

In recent years, consumers have been advised to use polyunsaturated fats instead of saturated fats in order to reduce the risk of heart disease. The dietary need for vitamin E increases when the intake of polyunsaturated fat increases. Cellular membranes containing polyunsaturated fats are more easily damaged by free radicals than those that contain saturated fats. In order to protect membranes containing high levels of polyunsaturated fat, increased consumption of both alpha and gamma tocopherols is essential.

Since the maximum blood levels of alpha and gamma tocopherol appear 4 to 6 hours after ingestion and drops to a basal level in about 12 hours, the maintenance of optimum levels of vitamin E in the blood requires taking Gamma E twice a day (morning and evening).

There are many forms of vitamin E available in the marketplace, and the efficacy of each is different. There are the natural forms of vitamin E and the synthetic forms. The synthetic forms are much less active than the natural forms, but there are also differences in activity among the natural forms. Natural vitamin E comes in two main forms; the unesterified forms that include d’alpha tocopherol and d’gamma tocopherol, and the esterified forms that include d’alpha tocopheryl acetate and d’alpha tocopheryl succinate. The esterified forms, often referred to as co-natural, because they are only partly natural, are the most commonly available forms of the vitamin. The unesterified forms of vitamin E are absorbed directly from the digestive tract, whereas the esterified forms must be first converted to alpha tocopherol by pancreatic enzymes and bile before they are biologically active. This process can be inefficient in many people, and up to 50% of the esterified form may not be converted. In addition, beta, delta and particularly gamma tocopherols have significant activity, and in combination with alpha tocopherol, represent the most biologically active forms of the vitamin.

Very few conventional Vitamin E formulas contain any gamma tocopherol at all, and none contain the ideal ratio of tocopherols as provided by Gamma E.

In summary, compelling scientific research suggests that it is unwise to take vitamin E in the form of just alpha tocopherol, and that a combination of gamma and alpha tocopherols where gamma tocopherol is the predominate tocopherol is ideal^(2)(3)(4). Another important factor in evaluating natural vitamin E formulas is comparing the total tocopherols. One capsule of Gamma E, while containing 136 mg of alpha tocopherol (equivalent to 200 I.U.), also contains 168 mg of gamma tocopherol and 369 mg of total tocopherols. Gamma E contains up to 38% more total tocopherols (equivalent to 550 I.U) when compared to a typical 400 IU alpha tocopherol formula, which contains only 268 mg total tocopherols.

References

1. Proceedings of the National Academy of Sciences, Vol. 90, March 1993
2. Proceedings of the National Academy of Sciences, Vol. 94, April 1997
3. Proceedings of the National Academy of Sciences, Vol. 97, October 2000
4. Journal of the National Cancer Institute, Vol. 92, No.24, 2018-2023, December 20, 2000
5. Current Drug Targets 2003 Jan:4(1):45-54
6. American Journal of Clinical Nutrition 2003; 77: 700-6
7. American Journal of Clinical Nutrition, Vol. 74, No. 6, 714-722, December 2001
8. The FASB Journal, Vol 16, December 2002