(機器翻譯) 維生素 C 是人類必需的微量營養素，具有與其提供電子的能力相關的多效性功能。它是一種有效的抗氧化劑，也是生物合成和基因調控酶家族的輔助因子。維生素 C 通過支持先天和適應性免疫係統的各種細胞功能來促進免疫防禦。維生素 C 支持針對病原體的上皮屏障功能，並促進皮膚的氧化劑清除活性，從而潛在地防止環境氧化應激。維生素 C 在吞噬細胞（如嗜中性粒細胞）中積累，可增強趨化性、吞噬作用、活性氧的產生，並最終殺死微生物。它也是巨噬細胞感染部位消耗的中性粒細胞凋亡和清除所必需的，從而減少壞死/NETosis 和潛在的組織損傷。維生素 C 在淋巴細胞中的作用尚不清楚，但已顯示它可以增強 B 細胞和 T 細胞的分化和增殖，這可能是由於其基因調節作用。維生素C缺乏會導致免疫力受損和更易感染。反過來，由於炎症和代謝需求的增加，感染會顯著影響維生素 C 的水平。此外，補充維生素 C 似乎能夠預防和治療呼吸道和全身感染。預防感染需要膳食維生素 C 攝入量，如果不能達到飽和血漿水平（即 100-200 毫克/天），至少可以提供足夠的血漿水平，從而優化細胞和組織水平。相反，治療既定感染需要顯著更高（克）劑量的維生素來補償增加的炎症反應和代謝需求。
Vitamin C is an essential micronutrient for humans, with pleiotropic functions related to its ability to donate electrons. It is a potent antioxidant and a cofactor for a family of biosynthetic and gene regulatory enzymes. Vitamin C contributes to immune defense by supporting various cellular functions of both the innate and adaptive immune system. Vitamin C supports epithelial barrier function against pathogens and promotes the oxidant scavenging activity of the skin, thereby potentially protecting against environmental oxidative stress. Vitamin C accumulates in phagocytic cells, such as neutrophils, and can enhance chemotaxis, phagocytosis, generation of reactive oxygen species, and ultimately microbial killing. It is also needed for apoptosis and clearance of the spent neutrophils from sites of infection by macrophages, thereby decreasing necrosis/NETosis and potential tissue damage. 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. Vitamin C deficiency results in impaired immunity and higher susceptibility to infections. In turn, infections significantly impact on vitamin C levels due to enhanced inflammation and metabolic requirements. Furthermore, supplementation with vitamin C appears to be able to both prevent and treat respiratory and systemic infections. Prophylactic prevention of infection requires dietary vitamin C intakes that provide at least adequate, if not saturating plasma levels (i.e., 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 inflammatory response and metabolic demand.
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