Infections have a significant impact on vitamin C levels, due to the increased energy needs required by the body during inflammation. This nutrient, in fact, promotes the proliferation of lymphocytes, with a consequent increase in the generation of antibodies [79, 85, 92]. It is well known that infections increase oxidative stress and usually activate phagocytes that release ROS, so vitamin C is a well-known antioxidant that can counteract these effects by increasing phagocytosis and ROS generation and improving microbial killing [92–94]. Furthermore, supplementation with vitamin C appears to be able to prevent and treat respiratory and systemic infections [92]. High levels of this nutrient can enhance antimicrobial effects and increase serum levels of complement proteins, also playing an important role in IFN-γ production [85, 92, 95].