Tocotrienol may protect against DNA damage, says study
damage, considered an important trigger in cancer development, by
about 50 per cent, new research suggests.
Researchers from Universiti Kebangsaan Malaysia and tocotrienol-supplier, Golden Hope Bioganic, report that daily supplementation with a tocotrienol-rich supplement (Tri E Tocotrienol) showed greater effects in the older subjects, a sub-population with higher rates of DNA damage. "The effect of Tri E Tocotrienol is more obvious in older age, possibly reflecting a greater need for supplementation or a greater profound effect due to the larger amount of damage present," wrote the authors, led by Siok-Fong Chin, in the journal Nutrition. There are eight forms of vitamin E: four tocopherols (alpha, beta, gamma, delta) and four tocotrienols (alpha, beta, gamma, delta). Alpha-tocopherol (alpha-Toc) is the main source found in supplements and in the European diet, while gamma-tocopherol (gamma-Toc) is the most common form in the American diet. Tocotrienols (TCT) are only minor components in plants, although several sources with relatively high levels include palm oil, cereal grains and rice bran. While the majority of research on vitamin E has focused on alpha-Toc, studies into tocotrienols account for less than one per cent of all research into vitamin E. This is slowly changing, and the new study reports the results of a randomised, double-blinded placebo-controlled study with 64 subjects aged 37 to 78 assigned to receive daily supplements of tocotrienol-rich vitamin E (160 mg/d, Tri E Tocotrienol, Golden Hope Bioganic) for six months. The supplement contained all four tocotrienols and alpha-Toc in a ratio of 74:26 per cent, respectively. The researchers report that white blood cells from patients receiving the tocotrienol-rich supplement had significantly less DNA damage after three and six months of supplementation than those in the placebo group. Significant reductions were also observed for urinary levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker for oxidative stress in the supplementation group, relative to placebo. Supplementation with the tocotrienol-rich vitamin E also reduced the frequency of sister chromatid exchange (SCE), an exchange of genetic information between sister chromatids that may be related to tumours, particularly in the older participants (over 50). The mechanism of protection is related to oxidative stress and the quenching of reactive oxygen species by vitamin E, said the researchers. The free radical theory of ageing (FRTA) places free radicals at the front of causes for deterioration of physiologic function as people get older. "The results obtained suggested that supplementation with palm oil Tri E Tocotrienol reduced the level of DNA damage in healthy subjects, with a more pronounced effect observed in older adults," concluded the researchers. "These observations may indicate a possible relation between the molecular mechanisms involved in the formation and repair of DNA breaks with Tri E Tocotrienol supplementation." Source: Nutrition (Elsevier) Published on-line ahead of print, doi:10.1016/j.nut.2007.08.006 "Reduction of DNA damage in older healthy adults by Tri E Tocotrienol supplementation" Authors: Siok-Fong Chin, N.A. Abdul Hamid, A.A. Latiff, Z. Zakaria, M. Mazlan, Y.A.M. Yusof, A.A.Karim, J. Ibahim, Z. Hamid and W.Z.W. Ngah