Vitamin C Intervention for Critical COVID-19: A Pragmatic Review of the Current Level of Evidence
Patrick Holford 1,*, Anitra C. Carr 2, Masuma Zawari 2, Marcela P. Vizcaychipi 3,4
Founder of Institute for Optimum Nutrition, Ambassador House, Richmond TW9 1SQ, UK
Nutrition in Medicine Research Group, Department of Pathology & Biomedical Science, University of Otago, Christchurch 8140, New Zealand; firstname.lastname@example.org (A.C.); email@example.com (M.Z.)
Faculty of Medicine, Imperial College, London SW7 2AZ, UK; firstname.lastname@example.org
Intensive Care Medicine, Chelsea & Westminster Hospital, London SW10 9NH, UK
Abstract: Severe respiratory infections are characterized by elevated inflammation and generation of reactive oxygen species (ROS) which may lead to a decrease in antioxidants such as vitamin C and a higher requirement for the vitamin. Administration of intravenous vitamin C to patients with pneumonia and sepsis appears to decrease the severity of the disease and potentially improve survival rate. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes pneumonia, sepsis and acute respiratory distress syndrome (ARDS) in severe cases, and is referred to as coronavirus disease 2019 (COVID-19). Patients with COVID-19 infection also appear to have depleted vitamin C status and require additional supplementation of vitamin C during the acute phase of the disease. To date there have been 12 vitamin C and COVID-19 trials published, including five randomised controlled trials (RCTs) and seven retrospective cohort studies. The current level of evidence from the RCTs suggests that intravenous vitamin C intervention may improve oxygenation parameters, reduce inflammatory markers, decrease days in hospital and reduce mortality, particularly in the more severely ill patients. High doses of oral vitamin C supplementation may also improve the rate of recovery in less severe cases. No adverse events have been reported in published vitamin C clinical trials in COVID-19 patients. Upcoming findings from larger RCTs will provide additional evidence on vitamin supplementation in COVID-19 patients.