The protective effect of copper may stem from its role as an essential component of ceruloplasmin, a protein with ferrous oxidase activity that promotes the transport and release of iron ions within cells, thereby preventing the Fenton reaction and the massive generation of hydroxyl radicals caused by the accumulation of free iron and reducing the risk of T2DM by alleviating oxidative stress [41,42]. This evidence concerns the gene CP and type 2 diabetes mellitus.