Immune-enhancing role of vitamin C and zinc and effect on clinical conditions

Abstract

The present paper is intended to give an overview on the roles of vitamin C and Zn in immune functions. Vitamin C concentrations in the plasma and leucocytes rapidly decline during infections and stress. Supplementation of vitamin C improves components of the human immune system such as antimicrobial and natural killer (NK) cell activities, lymphocyte proliferation, chemotaxis and delayed-type hypersensitivity. Vitamin C contributes to maintaining the redox integrity of cells and thereby protects them against reactive oxygen species generated during the respiratory burst and in the inflammatory response. Similarly, Zn deficiency impairs cellular mediators of innate immunity such as phagocytosis, NK cell activity, and the generation of oxidative burst. Thus, both nutrients play important and complementary roles in immune function and the modulation of host resistance to infectious agents, reducing the risk, severity and duration of infectious diseases. A deficiency in one of these essential nutrients weakens immunity since vitamin C is crucial for cellular immunity and Zn for the production of antibodies.A large number of randomized controlled intervention trials with intakes of £1 g vitamin C and £30 mg Zn are available. These trials show that adequate intakes of vitamin C and Zn ameliorate symptoms and shorten the duration of respiratory tract infections including the common cold. Natural defences can only provide full protection when the body has sufficient Zn, as well as high levels of vitamin C.The physiological effects of vitamin C provide clear evidence and rationale for a number of ways in which it might help to protect against infection.

Essential Role of Vitamin C and Zinc in Child Immunity and Health

“…While vitamin C and zinc both support epithelial barriers, although by different mechanisms, they target different populations of phagocytic cells, thereby complementing each other to ensure an effective phagocytic response. 30,31,36,153,155 With regard to adaptive immunity, zinc is the key player. Zinc is essential for the process that causes stem cells in the bone marrow to form lymphocytes, and for the subsequent differentiation into B-and T-lymphocytes.…”

“…Finally, both vitamin C and zinc provide complementary antioxidant protection to exogenously derived and endogenously generated ROS. 12,36,152,153 There is, therefore, a good scientific rationale that the combination of vitamin C and zinc support immune functions and reduce the risk of infections as described further in the following sections.…”

Evaluation of the relationship between serum levels of zinc, vitamin B12, vitamin D, and clinical outcomes in patients with COVID‐19

“…6,7 Zinc is an essential micronutrient with potent immunoregulatory and antiviral properties that is involved in the growth and the maturation of immune cells, development and activation of lymphoid cells, regulation of inflammatory cytokines, and controlling oxidative stress. 8 Zinc deficiency is associated with immune system dysfunction, neurosensory disorders, decreased body mass, enhanced risk of inflammatory disorders, increased risk of incidence, and morbidity of viral pneumonia. 7 It is well recognized that vitamin D as an essential mediator of immune responses, has anti-infective, anti-inflammatory, and immunomodulant functions.…”