营养如何助您对抗新冠肺炎？

营养摄取对增强免疫系统以抵御新冠病毒至关重要。但若不幸染病该如何应对？本文将深入解析营养状态如何帮助预防重症，甚至辅助住院患者的治疗。

维他命C

维他命C是构成抗病毒免疫防御的关键要素。研究证实维他命C能加速上呼吸道感染康复[1]。更有研究显示高达82%新冠重症患者血浆维他命C浓度偏低（<0.4 mg/dL）[2]，虽属相关性数据，但暗示维他命C可能对预防病情恶化具有重要作用。

维他命C透过减轻炎症反应保护肺部组织，预防继发性败血症（扩散性感染，致死率高）[3]。多国已将高剂量静脉注射维他命C纳入住院患者治疗方案，相关临床试验仍在进行中[4]。

谷胱甘肽

作为强效抗氧化剂，谷胱甘肽能调节病毒感染期的炎症反应。当免疫细胞攻击新冠病毒时会产生大量氧化压力，需靠抗氧化剂中和其对组织的损伤。身为人体主要抗氧化剂，谷胱甘肽缺乏将导致抗氧化防御崩溃，加剧氧化压力。

研究比较各年龄层健康群体与住院患者的谷胱甘肽水平，发现新冠患者普遍存在严重谷胱甘肽缺乏、氧化压力激增及氧化损伤加剧。年轻患者数据尤令人意外（该群体原本应保持较高水平）[5]。另一研究结论指出：「氧化压力升高与抗氧化指标下降，会恶化住院患者病情」[6]。

随着年龄增长，谷胱甘肽水平自然下降[7]，这可能解释为何长者更易出现新冠重症。

维他命D

人体每类细胞均存在维他命D受体，其功能多元性几乎影响所有健康层面。学界对其在免疫领域的作用高度关注，从自身免疫疾病、癌症到病毒感染均有涉猎。

2021年突破性研究发现，对维他命D水平偏低（25OHD <30 ng/m）的患者群组进行分析，未补充维他命D3者住院超过8天的风险增加1.9倍。更显著的是，接受维他命D治疗的患者死亡率下降2.14倍，即使存在共病症亦然[8]。

研究人员更断言补充维他命D对新冠治疗「不可或缺」。⁸

硒

这种土壤中的必需微量矿物质虽需求甚微，却是调节氧化压力、氧化还原及免疫反应的关键[9]。

中国涉及14,045例病例的大型研究显示，缺硒地区新冠死亡率较正常地区高出2.7倍[10]，此发现为硒元素治疗潜力提供重要线索。

References:

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2. Tomasa-Irriguible, T.M., Bielsa-Berrocal, L. COVID-19: Up to 82% critically ill patients had low Vitamin C values. Nutr J20, 66 (2021). https://doi.org/10.1186/s12937-021-00727-z
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