There is marked controversy on the beneficial levels of selenium (Se) to be used as a dietary supplement. The form of supplemented Se and the baseline plasma or serum Se status among supplemented populations are generally considered as crucial factors in this controversy. However, responses to supplemented Se can further vary with other factors, including health status, lifestyle, demographics and genetics. In the present study, the putative supplementation benefits of Se as 200 μg/day selenised yeast for six months were evaluated among a stratified male population from Auckland, New Zealand. Our study considered changes in surrogate biomarkers for cancer including antioxidant selenoenzymes glutathione peroxidase (GPx) and thioredoxin reductase activity (TR) levels, basal and peroxide-induced DNA damage levels. A total of 569 subjects self-reporting a European ancestry signed in for the study and provided answers to a basic demographic, health and lifestyle questionnaire. The effects of Se supplementation on biomarkers showed significant variability based on age, BMI, health status and seleno-genotypes of SELS rs4965373, GPx1 rs1050450, and SEPP1 rs3877899. The data indicate that the benefits of supplementary Se vary significantly across a population, based on demographics, lifestyle, health conditions and seleno-genotypes. As a contrast to “one-size-fits-all” nutritional interventions, these observations collectively inform rational targeting and personalisation of future Se-based dietary supplementation in regards to cancer chemoprevention strategies. This work also represents a way forward in critically understanding Se requirements in populations.

Benefit variability by age, BMI, health status, nutrigenetics, personalising chemoprevention, seleno-genotypes, Se supplementation.

Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.