Nutritional risk of vitamin D, vitamin C, zinc, and selenium deficiency on risk and clinical outcomes of COVID-19: A narrative review

The pathogenicity of the current coronavirus disease (COVID-19) shows postulates that optimal status of essential nutrients is crucial in supporting both the early viraemic and later hyperinflammatory phases of COVID-19. Micronutrients such as vitamin C, D, zinc, and selenium play roles in antioxidant, antiinflammatory, antithrombotic, antiviral, and immuno-modulatory functions and are useful in both innate and adaptive immunity. The purpose of this review is to provide a high-level summary of evidence on clinical outcomes associated with nutritional risk of these micronutrients observed in patients with COVID-19. A literature search was performed on PubMed and Google Scholar to obtain findings of crosssectional and experimental studies in humans. The search resulted in a total of 1212 reports including all nutrients, but only 85 were included according to the eligibility criteria. Despite the diversity of studies and the lack of randomized clinical trials and prospective cohorts, there is evidence of the potential protective and therapeutic roles of vitamin C, D, zinc, and selenium in COVID-19. The findings summarized in this review will contribute to guide interventions in clinical practice or in future clinical studies. (C) 2021 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.