The results of clinical trials performed by Jacobs et al. did not confirm the causal role of selenium in the development of insulin resistance or type 2 diabetes, as no significant differences in β-cell function (HOMA2-%β) and insulin sensitivity (HOMA2-%S) were observed between individuals receiving selenium supplementation (200 μg/day) and those in the placebo group over a 2.9-year period. This evidence concerns the gene INS and type 2 diabetes mellitus.