Selenium and prostate cancer:
Researchers examined the association between prostate cancer incidence and pre-diagnostic selenium concentrations in toenails. The level of selenium in toenails reflects intake from dietary and supplementary sources. Yoshizawa et al. prospectively examined toenail selenium levels in 181 men who later developed advanced prostate cancer (stages C and D) during 2–7 years of follow-up. Results showed the mean toenail selenium level was significantly higher in control subjects than in cancer subjects. It was found that higher selenium levels were associated with a reduced risk of advanced prostate cancer. When subjects in the highest 20 percent for selenium status were compared with those in the lowest 20 percent, those with the highest selenium status were half as likely to get prostate cancer as those with the lowest levels. The authors reporting an odds ratio (OR) for prostate cancer of 0.4 comparing the highest with the lowest quintile of toenail selenium content. After additionally controlling for family history of prostate cancer, body mass index, calcium intake, lycopene intake, saturated fat intake, vasectomy, and geographical region, the OR was 0.35. These findings suggest that higher selenium intakes may reduce the risk of prostate cancer. (6)
