Essential trace mineral Selenium (Se), has been noted to possess cancer-protective effects. The variation in human dietary intake is reflected in the global variation in blood Se levels , observed in Europe .
The nested case control (NCC) study, performed by the Danish Cancer Society Research Center, identified 784 cases with incident prostate cancer in 2007 from the ‘Diet, Cancer and Health’ cohort that consisted of 27,179 men.
When compared to a subset of controls, two-thirds (525) of the cases had the advanced from of the disease at the time of diagnosis, and among these 170 had the higher-grade form of cancer. 305 cases died (212 from prostate cancer) during follow-up through 2012.
The team concluded that levels of plasma Se were not associated with the risk of total and advanced prostate cancer, but higher levels of this biomarker was associated with a lower risk of the higher grade disease.
Clash of Se studies
Evidence from previous studies has proved conflicting. The Selenium and Vitamin E Cancer Prevention Trial found no effect of 200 µg of Se supplementation per day on the incidence of prostate cancer in a high-Se population.
In contrast a post hoc analysis revealed that Se supplementation increased the risk of high-grade prostate cancer in men with the highest baseline Se levels .
“For high-grade prostate cancer, statistically significant lower risks were seen with higher plasma levels of Se,” the researchers noted.
“Among prostate cancer patients, there seemed to be a slightly lower risk of overall death associated with higher pre-diagnostic plasma Se levels.”
In addition, a strong correlation between plasma Se and selenoprotein P was observed indicating that both Se measures were relevant as markers of Se exposure in a low-Se population.
“Our finding of a strong correlation is consistent with findings in other European populations in which correlations between 0.60 and 0.88 were reported,” the study noted.
Source: British Journal of Nutrition
Published online ahead of print, doi:10.1017/S0007114516000726
“Selenium status and risk of prostate cancer in a Danish population.”
Authors: Malene Outzen, Anne Tjønneland, Erik H. Larsen, Søren Friis, Signe B. Larsen, Jane Christensen, Kim Overvad and Anja Olsen.