Written by Michael Lelah, Ph.D., Conference paper presented at the American Oil Chemists’ Society (AOCS) Hot Topics Symposium, May 2006. Theme: Controversy over the Role of Natural Vitamin E in Reducing Leading Causes of Death.
Physiologically, Vitamin E has antioxidant properties. It is the major chain-breaking antioxidant in body tissue and is the first line of defense against lipid peroxidation. Vitamin E protects cell membranes at early stages and is a free radical scavenger, interacting with other antioxidant nutrients within an oxidant network. Vitamin E also has other physiological effects – immunostimulation, and reducing the severity of prostaglandin-mediated disorders such as inflammation and circulatory irregularities. It also has direct chemical function. It inhibits the conversion of nitrites to nitrosamines.
Vitamin E is not a typical vitamin. It does not function as a cofactor, and elimination from the diet does not produce a disease with rapidly developing symptoms, such as scurvy or beri beri.
The recommended dietary intake is 15 IU for males and 12 IU for females, as established by the Food and Nutrition Board of the National research Council in 1989. 1 mg = 1.49 IU (international Units). To prevent deficiency disease, this level of intake per day is adequate. However, it is generally recognized that to prevent lipid peroxidation and free radical damage, for optimum health, the dose should be 150 IU. Further, for therapeutic results, doses of 400+ IU are needed.
Safety of Vitamin E: In a 1988 review of 45 studies, very low toxicity of single or chronic doses was determined. There were 6 major double-blind, placebo controlled studies with daily intake of 600 – 3200 IU, from 3 weeks to 6 months in duration, with very few side effects, and no specific consistent side effect. No evidence of carcinogenicity, mutagenicity, or teratogenicity has been observed.
Natural Vitamin E is found in the diet in oils and fats – especially vegetable oils such as wheat germ oil. Also found in sunflower and almonds (nuts) and wheat germ (grains). In the U.S., 65% of Vitamin E intake is from salad oils, margarine and butter. The normal diet contains about 10-13 IU/day. Soy is the most widely used commercial source for natural Vitamin E.
Synthetic Vitamin E: Unlike other vitamins, synthetic Vitamin E is not biochemically equivalent to the natural forms. Synthetic Vitamin E is a mixture of 8 stereoisomers, only one of which is equivalent to d-alpha-tocopherol. Synthetic Vitamin E is produced from petrochemicals – by the reaction of isophytpol with trimethylhydrquinone.
In review of comparison studies between natural Vitamin E and synthetic Vitamin E in animals and in humans, natural sourced Vitamin E is at least 2 x as effective as synthetic Vitamin E based on physiological and pharmacological markers. There are no good studies comparing the effects of natural Vitamin E vs. synthetic Vitamin E on diseases. In addition, other work presented at this conference indicates that many of the components of natural Vitamin E, gamma-tocotrienol, for example, have their own specific physiological benefits.
Vitamin E Esters: Although free form Vitamin E is what is used in the body, most dietary supplements are in the acetate or succinate ester form. These forms are more stable and are converted (hydrolyzed) into the free form in the body. The acetate form is an oil. This form is suitable for use in soft gels and in cosmetic applications. The succinate form is a solid – and is the preferred form for multivitamins.
In conclusion, natural Vitamin E is a major safe antioxidant nutrient that consists of 8 different components. It is chemically different from synthetic Vitamin E. The natural form is at least twice as effective physiologically than the synthetic form. In addition new research is showing specific health benefits of the individual natural forms.
References:
- Packer, L., Vitamin E is Nature’s Master Antioxidant, Science & Medicine, 1(1);54-63, 1994.
- Vitamin E Fact Book, VERIS (Vitamin E Research and Information Service), LaGrange IL, 1994.
- Callem, J., Smith, M.D., All About Vitamin E, Avery, NY, 1999.
- A Comparison of Natural and Synthetic Vitamin E, 1999
- Jiang, Q., Christen, S., Shigenaga, M.K., Ames, B.N., Gamma-Tocopherol, The Major Form of Vitamin E in the US Diet, Am. J. Clin. Nutr. 74:714-722, 2001.
