VDR and infection: Recently, the role of vitamin D in intestines has been described by Malaguarnera, who reported the role of vitamin D in the maintenance of gut homeostatis through a local synthesis of 1α,25(OH)2D3 and VDR expression, emphasizing that an optimal 1α,25(OH)2D3 status is fundamental, as it participates in several regulatory activities regarding not only calcium absorption but also infection protection, epithelial barrier function preservation and gut microbiota modulation.