Yesterday, I talked about the rumors about Vitamin E in relation to prostate health and cancer. Below are some studies about why Vitamin E is good for you especially those that are not synthetic ones.
It is important to recognize that ‘tocopherols’ is a general term used for four different forms of vitamin E, namely alpha-tocopherol, beta-tocopherol, delta-tocopherol and gamma-tocopherol, which are found naturally in food sources
containing vitamin E, vegetable oils in particular.
Vitamin E in food sources also contains four other compounds, these being referred to as tocotrienols (again, alpha-, beta-, delta- and gamma- forms), but these normally occur at trace levels. However, the synergistic role of all 8 forms of vitamin E as essential nutrients is being increasingly well elucidated through research. Of the tocopherols in corn oil and soybean oil, for example, gamma-tocopherol contributes to 77 and 70 %, delta-tocopherol to 2 and 23%, and alpha-tocopherol to 14 and 7%, respectively (personal communication, Professor Tom Saldeen, internationally recognised expert on vitamin E).
Alpha-tocopherol, being just one form, exhibits different biological responses in humans and animals compared with natural blends of tocopherols (referred to as ‘mixed tocopherols’, as used in the Total Health supplement). Alpha-tocopherol, at higher dosages, may trigger responses which are antagonistic to normal metabolic function and are likely to be important factors in the seeming conflict between large numbers of epidemiologic studies, which have consistently shown that higher intakes of vitamin E in foods are associated with reduced risk of chronic diseases such as heart disease and cancer, and a number of randomized controlled trials, undertaken always with alpha-tocopherol (synthetic or purified naturally-derived, pharmaceutical form, notably alpha-tocopheryl acetate) and not ‘mixed tocopherols’.
It is therefore generally not possible to extrapolate the results from randomized trials using alpha-tocopherol as a means of demonstrating probable effects on either efficacy or safety. Nevertheless, it should be stated at the outset, even with the most cynical view of the literature, that the dosage of tocopherols (including alpha-tocopherol) within the Total Health supplement is well within the range of consumption found in the UK population.
One IU of vitamin E is defined as the biological equivalent of 0.667 milligrams of RRR-alpha-tocopherol (formerly named d-alpha-tocopherol, or of 1 milligram of all-rac-alpha-tocopheryl acetate (commercially referred to as dl-alpha-tocopheryl acetate, the form widely used in randomised trials). The EVM (2003) estimated maximum intakes for vitamin E (food and supplements) as 690 mg of d-alpha-tocopherol equivalents.
The amount of vitamin E in the Total Health supplement is 250 IU (d-alpha-tocopherol equivalents) which equates to 169 mg, ensuring that it is less than 25% of the maximum intake determined by the EVM. Seen in the context of risk assessment, including the fact that the Total Health Supplement includes mixed tocopherols, rather than only alpha-tocopherol, means that this dosage does not constitute any risk to health and therefore could not give rise to any side effects (for further interpretation of the safety of vitamin E in relation to the Total Health supplement see section entitled Vitamin E risk assessment by the EVM, below). Vitamin E you may have somebody visiting you
In a study on more than 20,000 men, patients who developed prostate cancer had significantly lower blood levels of gamma-tocopherol than men who developed prostate cancer (Huang HY, Alberg AJ, Norkus EP, Hoffman SC, Comstock GW, Helzlsouer KJ. Prospective study of antioxidant micronutrients in the blood and the risk of developing prostate cancer. American Journal of Epidemiology, 2003; 157: 335-44; Helzlsouer KJ, Huang HY, Alberg AJ, Hoffman S, Burke A, Norkus EP, Morris JS, Comstock GW. Association between alpha-tocopherol, gamma-tocopherol, selenium, and subsequent prostate cancer. Journal of the National Cancer Institute 2000; 92: 2018-23). The higher the blood gamma-tocopherol levels, the lower the risk of prostate cancer.
Men with the highest levels were 80% less likely to develop prostate cancer compared to men with the lowest levels. Gamma-tocopherol has the ability to inhibit the growth of prostate cancer cells to a greater degree than alpha-tocopherol
(Gysin R, Azzi A, Visarius T. Gamma-tocopherol inhibits human cancer cell cycle progression and cell proliferation by down-regulation of cyclins. The Federation of American Societies for Experimental Biology (FASEB) Journal 2002; 16: 152-4; Moyad MA, Brumfield SK, Pienta KJ. Vitamin E, alpha- and gamma-tocopherol, and prostate cancer. Seminars in Urologic Oncology 1999; 17: 85-90). Gamma-tocopherol and delta-tocopherol have also been found to be superior to alpha-tocopherol in inhibiting neoplastic transformation of certain cells (Cooney RV, Franke AA, Harwood PJ, Hatch-pigott V, Custer LJ, Mordan LJ. Gamma-tocopherol detoxification of nitrogen dioxide: superiority to alpha-tocopherol. Proceedings of the National Academies of Sciences USA 1993; 90: 1771-5; McIntyre BS, Briski KP, Gapor A, Sylvester PW. Antiproliferative and apoptotic effects of tocopherols and tocotrienols on preneoplastic and neoplastic mouse mammary epithelial cells. Proceedings of the Society for Experimental Biology and Medicine 2000; 224: 292-301). Additionally, a relatively recent pilot, randomised controlled trial, namely the Prevention Research Veteran Affairs E-vitamin Nutrition Trial demonstrated positive results and no side effects of vitamin E in relation to prostate cancer risk (Hernaandez J, Syed S, Weiss G, Fernandes G, von Merveldt D, Troyer DA, Basler JW, Thompson IM Jr. The modulation of prostate cancer risk with alpha-tocopherol: a pilot randomized, controlled clinical trial. Journal of Urology 2005 Aug; 174(2):519-22).