Selenium supplementation and prostate health in a New Zealand cohort

Background: There is variable reporting on the benefits of a 200μg/d selenium supplementation towards reducing prostate cancer impacts. The current analysis is to understand whether stratified groups receive supplementation benefits on prostate health. Methods: 572 men were supplemented with 200µg/d selenium as selinized yeast for six months, and 481 completed the protocol. Selenium and prostate-specific antigen (PSA) levels were measured in serum at pre- and post- supplementation. Changes in selenium and PSA levels subsequent to supplementation were assessed with and without demographic, lifestyle, genetic and dietary stratifications. Results: The post- supplementation selenium (p=0.002) and the gain in selenium (p<0.0001) by supplementation were significantly dependent on the baseline selenium level. Overall, there was no significant correlation between changes in PSA and changes in selenium levels by supplementation. However, stratified analyses showed significant inverse correlation between changes in PSA and changes in selenium in men below the median age (p=0.048), never-smokers (p=0.031), men carrying the GPX1 rs1050450 T allele (CT, p= 0.022 and TT, p= 0.011), dietary intakes above the recommended daily intake (RDI) for zinc (p<0.05), and below the RDI for vitamin B12 (p<0.001). Conclusions: The current analysis shows the influence of life factors on prostate health benefits of supplemental selenium.