Immune-Enhancing Role of Vitamin C and Zinc and Effect on Clinical Conditions

Abstract

Vitamin C concentrations in the plasma and leukocytes rapidly decline during infections and stress. Supplementation of vitamin C was found to improve components of the human immune system such as antimicrobial and natural killer 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. Likewise, zinc undernutrition or deficiency was shown to impair cellular mediators of innate immunity such as phagocytosis, natural killer cell activity, and the generation of oxidative burst. Therefore, both nutrients play important roles in immune function and the modulation of host resistance to infectious agents, reducing the risk, severity, and duration of infectious diseases. This is of special importance in populations in which insufficient intake of these nutrients is prevalent. In the developing world, this is the case in low- and middle-income countries, but also in subpopulations in industrialized countries, e.g. in the elderly. A large number of randomized controlled intervention trials with intakes of up to 1 g of vitamin C and up to 30 mg of zinc are available. These trials document that adequate intakes of vitamin C and zinc ameliorate symptoms and shorten the duration of respiratory tract infections including the common cold. Furthermore, vitamin C and zinc reduce the incidence and improve the outcome of pneumonia, malaria, and diarrhea infections, especially in children in developing countries.

Vitamin C in Disease Prevention and Cure: An Overview

“…Further, it has been shown that AA blocks pathways that lead to apoptosis of T-cells and thus stimulate or maintain T-cell proliferation to attack the infection. This mechanism has been proposed for the enhanced immune response observed after administration of vitamin C during rhinitis [36,37].…”

“…Supplementation of vitamin C has been shown to improve components of the human immune system such as antimicrobial and NK cell activities, lymphocyte proliferation, chemotaxis, and delayed-type hypersensitivity as discussed above. Vitamin C contributes in maintenance of the redox integrity of cells and thereby protects them against ROS generated during the respiratory burst and in the inflammatory response [197].…”

An Overview of the Characteristics and Function of Vitamin C in Various Tissues: Relying on its Antioxidant Function

“…Supplementation of vitamin C was found to improve components of the human immune system such as antimicrobial and natural killer cell activities, lymphocyte proliferation, chemotaxis, and delayed-type hypersensitivity. Several cells of the immune system can indeed accumulate vitamin C and need the vitamin to perform their task, especially phagocytes and t-cells [60]. Thus a vitamin C deficiency results in a reduced resistance against certain pathogens whilst a higher supply enhances several immune system parameters.…”

Mudanças no estilo de vida e fatores de risco para doenças crônicas não transmissíveis e sistema imune de mulheres sedentárias

“…Esta vitamina e os leucócitos rapidamente declinam durante as infecções e o estresse. Outros observaram que o aumento da concentração plasmática de vitamina C era associado à melhora dos componentes do sistema imunológico, tais como, a atividade antimicrobiana e das células natural killer, a proliferação de linfócitos e a quimiotaxia 19 . A vitamina C e os linfócitos destas mulheres estavam em concentrações consideradas deficientes, o que poderia contribuir para piora das defesas imunológicas e da neutralização da produção de radicais livres.…”