Among the main activities of zinc in immune function there are: maintaining skin and mucosal integrity (e.g., cofactor for metalloenzymes required for cell membrane repair) [118]; improving the cytotoxic activity of NK cells [79, 82] and the phagocytic capacity of monocytes [64]. It is involved in the complement activity and in the production of IFN-γ [92, 95]; it is an important anti-inflammatory agent [119] and helps modulate the release of cytokines [95] by attenuating the development of pro-inflammatory Th17 and Th9 cells [64]. Furthermore, by influencing the generation of cytokines such as IL-2, IL-6 and TNF, it has antioxidant effects that protect against ROS and reactive nitrogen species [120]. Zinc also induces the proliferation of cytotoxic T cells [62] and is involved in the production of Th1 cytokines and thus supports the Th1 response [95]. It is essential for the intracellular binding of tyrosine kinase to T cell receptors, which is required for T cell development, differentiation and activation [118] and induces the development of Treg cells and is therefore important for maintaining immune tolerance [120].