ACE2 and Zinc deficiency: Although the relation of ZIPs and ZnTs to saliva secretory and gustatory functions still needs to be elucidated, if the expression of zinc transporters is dysregulated in association with COVID-19-induced intracellular zinc deficiency, cellular zinc homeostasis could be disturbed, affecting the activity of zinc-metalloenzymes (carbonic anhydrase and ACE2) in taste buds and salivary glands with the subsequent functional declines of taste perception and saliva secretion.