The activated form of vitamin D, 1,25(OH)2D, suppresses renin biosynthesis, and vitamin D deficiency stimulates renin production; based on its suppression of the RAAS system in animal models, vitamin D supplementation shows beneficial effects on albuminuria, which suggests that vitamin D supplementation may prevent the progression of kidney disease to kidney failure like other RAAS blockers [27]. Here, REN is linked to vitamin D deficiency.