title: Down-regulation of oxidative DNA lesions in human mononuclear cells after antioxidant supplementation correlates to increase of gamma-tocopherol.
abstract: The protective effect of vitamin E supplements has been questioned, possibly because they often contain only alpha-tocopherol, and recent studies indicate that gamma-tocopherol also has important properties. The aim of this study was to investigate whether the levels of DNA lesions in middle-aged, overweight males could be reduced by consumption of low doses of an antioxidant supplement for six weeks, designed to imitate a balanced diet. The participants (n=60) were randomly divided into: placebo, single-, and double-dose groups. Genotoxic and oxidative DNA lesions in mononuclear cells were measured with the Comet assay, before and after supplement administration. Furthermore, a cell study was performed to investigate if pre-incubation of a human lung cell line (A549) with alpha- and gamma-tocopherol (5 and 50 microM for 23 hours) could protect against induced oxidative DNA lesions as measured by the Comet assay. The level of oxidative DNA lesions in the double-dose group was significantly lower than in the control group. Oxidative DNA lesions correlated only to changes in serum gamma-tocopherol, and not alpha-tocopherol. In the cell study, only gamma-tocopherol protected cells against induced oxidative DNA lesions. We therefore hypothesize that gamma-tocopheol rather than alpha-tocopherol is involved in reducing oxidative DNA lesions.
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden. clara.johansson@ki.se
authors.forename: Clara
authors.initials: C
authors.lastname: Johansson
authors.forename: Elisabet
authors.initials: E
authors.lastname: Rytter
authors.forename: Jonas
authors.initials: J
authors.lastname: Nygren
authors.forename: Bengt
authors.initials: B
authors.lastname: Vessby
authors.forename: Samar
authors.initials: S
authors.lastname: Basu
authors.forename: Lennart
authors.initials: L
authors.lastname: Möller