The Story of Vitamin C and its Versions in Sepsis and COVID-19: Traditional Review

The multifaceted role of vitamin C, also known as ascorbic acid, in cellular homeostasis has been underscored, with particular emphasis on its involvement as a co-factor in crucial hydroxylation reactions, facilitation of collagen formation, and participation in enzymatic reactions crucial for maintaining cellular and tissue functions. Moreover, its attributed capacity to neutralize free radicals, protect cells against oxidative stress, and mitigate inflammatory responses accentuates its potential therapeutic significance. This review aims to comprehensively explore the contemporary understanding of vitamin C's therapeutic implications in sepsis and coronavirus disease-2019 (COVID-19) based on the relevant publications from the past years. While previous investigations have encompassed a range of study designs, including epidemiological research, this presented paper deliberately narrows its focus to recent randomized clinical trials (RCTs) and the latest systematic meta-analysis involving only RCTs, providing a higher level of evidence than observational studies. An exception is made for a meta-analysis examining vitamin C's role in COVID-19 patients, including previous RCTs and retrospective studies. The question in the present paper is whether vitamin C is efficacious in preventing and treating critical illnesses, particularly sepsis and COVID-19. The current evidence is still insufficient based on available publications from the last years and recent metaanalyses on this topic. Accordingly, larger high-quality randomized clinical trial studies are needed to provide more definitive insights into the efficacy of vitamin C in addressing critical illnesses.