Vitamin D, its “non-classic” actions and it utility in the COVID-19 pandemic

Abstract

The discovery that the synthesis of 1-25-vitamin D is not only renal and that the enzyme 1 alpha hydroxylase is found in numerous tissues of the body, together with the evidence of the association between vitamin D deficiency and the presence of non-bone diseases (cancer, multiple sclerosis, autoimmune diseases, etc.), gives us the possibility of trying to prevent these conditions. Placebo-controlled supplementation studies have not provided positive results for certain conditions, but some of these trials have been carried out on populations with “sufficient” and not “deficient” vitamin D levels. However, other meta-analyses have shown prevention of some conditions (respiratory infections, prediabetes) in groups of patients with deficiencies who were given supplements. There is also evidence of antiviral effect of vitamin D. Its anti-infective and immunomodulatory action and its effect upon the renin–angiotensin system, stimulating the angiotensin-converting enzyme 2 (the SARS-CoV virus receptor), nowadays allow us to think that, in high levels, COVID-19 infection could be less likely or serious. Vitamin D supplementation is adequate for preventing diseases in patients with deficiencies; administering vitamin D within the 2020 pandemic, even without having tested it in high-risk populations, could diminish the incidence of this disease.