The influence of high doses of vitamin C and zinc on oxidative DNA damage

Abstract

Background: The influence of interactions between reactive oxygen species (ROS) and dietary antioxidants and their influence on cancer is not clear. It is believed that this effect is mediated by decreased oxidative damage to DNA. The aim of this study was to further investigate the in vitro DNA protective or damaging effects of dietary antioxidants using the single cell gel electrophoresis (Comet) assay.

Materials and methods: Stimulated and unstimulated lymphocytes of 10 individuals were cultured with and without different concentrations of vitamins C and zinc and damaged with H2O2.

Results: DNA damage measured by Olive tail moment in the Comet assay showed a non-significant trend to reduce DNA strand breaks at low vitamin and trace element concentrations. At higher vitamin C and zinc doses, DNA damage was significantly increased.

Conclusion: The in vitro data of the present study suggest that high dosage intake of vitamin C and zinc may cause more harm than benefit. There is good evidence that health-related effects of dietary antioxidants strongly depend on individual genetic susceptibilities and health status.