Vitamin C and Children s Immunity: Facts & Fictions

Introduction: The proper health and development of children depends on several factors, including appropriate nutrition. Nutrition plays an important role in immune system, among which vitamin C has been one of the most widely discussed micronutrients with some controversies. The role of vitamin C in lymphocytes is less clear, but it has been shown to enhance differentiation and proliferation of B- and T-cells, likely due to its gene regulating effects. The aim of the present study was to summarize the importance of this role. Methods: In a library-based study, key terms related to vitamin C and immune system of MESH were search using information databases GoogleScholar, Pubmed, and SID during 1987-2017 as period of time. Results: Out of 3460 articles, 1061 related titles were studied and finally, 53 human sample articles were selected. Based on the findings of this research, vitamin C concentration in both plasma and leukocytes rapidly reduced during infections and stresses. It is important and necessary in all stressful conditions associated with inflammatory processes that involve the immune system. Recent research has also indicated an important role for vitamin C in regulation of DNA and histone methylation by acting as a cofactor for enzymes, which hydroxylate these epigenetic marks. Upon phagocytosis or activation with soluble stimulants, vitamin C is depleted from neutrophils in an oxidant-dependent manner. Vitamin C appears to be able to both prevent and treat respiratory and systemic infections by enhancing various immune cell functions. Vitamin C prescription could improve the components of the human immune system, through NK cells’ activity, lymphocyte proliferation, chemo-static and delayed sensitivity. Vitamin C deficiency results in a reduced resistance against certain pathogens whilst a higher supply enhances several immune system parameters. Prophylactic prevention of infection requires dietary vitamin C intakes that provide at least adequate, if not saturating plasma levels (100–200 mg/day), which optimize cell and tissue levels. In contrast, treatment of established infections requires significantly higher (gram) doses of the vitamin to compensate for the increased metabolic demand. Conclusion: Ensuring adequate intake of vitamin C through the diet or via supplementation, especially in groups such as children or in individuals exposed to risk factors for vitamin C insufficiency, is required for proper immune function and resistance to infections.

کلیدواژه ها:

Vitamin C ، Immunity ، Children.