Nutritional perspectives for the prevention and mitigation of COVID-19

Abstract

Worldwide, there is an array of clinical trials under way to evaluate treatment options against coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2. Concurrently, several nutritional therapies and alternative supportive treatments are also being used and tested to reduce the mortality associated with acute respiratory distress in patients with COVID-19. In the context of COVID-19, improved nutrition that includes micronutrient supplementation to augment the immune system has been recognized as a viable approach to both prevent and alleviate the severity of the infection. The potential role of micronutrients as immune-boosting agents is particularly relevant for low- and middle-income countries, which already have an existing high burden of undernutrition and micronutrient deficiencies. A systematic literature review was performed to identify nutritional interventions that might prevent or aid in the recovery from COVID-19. The PubMed, ScienceDirect, Cochrane, Scopus, Web of Science, and Google Scholar databases were searched electronically from February to April 2020. All abstracts and full-text articles were examined for their relevance to this review. The information gathered was collated under various categories. Deficiencies of micronutrients, especially vitamins A, B complex, C, and D, zinc, iron, and selenium, are common among vulnerable populations in general and among COVID-19 patients in particular and could plausibly increase the risk of mortality. Judicious use of need-based micronutrient supplementation, alongside existing micronutrient fortification programs, is warranted in the current global pandemic, especially in low- and middle-income economies.

Trial registration: ClinicalTrials.gov NCT04304053 NCT04318444 NCT04251871 NCT04303507 NCT04321174 NCT04312243 NCT04308668.

Keywords: COVID-19; SARS-CoV-2; immune system; influenza; micronutrients; nutrition.

Figure 1

Effect of nutrients on the mechanisms of innate and adaptive immunity. (1) Virus attaches to bronchial epithelial cell layer. (2) Alveolar neutrophils and macrophages attack the virus. (3) Infected bronchial epithelial cells release cytokines (IFN-1, TNF-α, IL-16, IL-33, IL-25) to alert the neighboring cells and activate the innate immune cells, ie, neutrophils, natural killer cells, dendritic cells, and macrophages. (4) Alveolar neutrophils and macrophages engulf the virus for phagocytosis. (5) After multiple viral replications, epithelial cells burst and release new daughter viral copies, which results in activation of the dendritic cells. (6) Dendritic cells activate T-lymphocyte helper cells and B-lymphocyte cells. (7) T-helper 12 cells activate the cytotoxic T-lymphocyte cells. (8) B lymphocytes divide into memory and plasma cells, and plasma cells produce antibodies against the virus. Abbreviations: IFN, interferon; Ig, immunoglobulin; IL, interleukin; TNF, tumor necrosis factor.

Figure 2

Role of vitamins E, D, and C in innate and adaptive immunity. Abbreviations: COX, cyclooxygenase; Ig, immunoglobulin; IL, interleukin; MHC, macrophage histocompatibility complex; NK, natural killer; NO, nitric oxide; PEG, polyethylene glycol; TNF, tumor necrosis factor.