Prostate cancer has been associated with low serum selenium concentration. To investigate the mechanisms by which selenium affects gene expression prostate tissue, researchers set out to measure activity of glutathione peroxidase in men with relatively high serum selenium concentration (1).
The researchers measured serum selenium concentration in 98 men using atomic absorption spectrometry. Afterward, 12 men were selected for having the highest serum selenium concentration and another 12 were identified as having the lowest serum selenium concentration. Fresh prostate tissue samples were taken of the selected men to measure selenium concentration and glutathione peroxidase activity.
The study, which was published in July 2007, reported a positive correlation found between a higher serum selenium concentration and a prostate tissue concentration. However, there was no significant increase of glutathione peroxidase activity associated with the higher concentration of selenium concentration.
Discussion: Because the subjects of this study were already were identified as having high serum selenium concentrations, the results indicate simply that glutathione peroxidase activity is not increased by greater concentration of selenium beyond a certain requirement. The data suggest selenium dietary intake exceeding established amounts to correct deficiency do not present any additional benefit in prevention of prostate cancer.
1. Takata Y, Morris JS, King IB, Kristal AR, Lin DW, Peters U. Correlation between selenium concentrations and glutathione peroxidase activity in serum and human prostate tissue. Prostate 2009.