Immunologic Effects of Vitamin D on Human Health and Disease

Abstract

Vitamin D is responsible for regulation of calcium and phosphate metabolism and maintaining a healthy mineralized skeleton. It is also known as an immunomodulatory hormone. Experimental studies have shown that 1,25-dihydroxyvitamin D, the active form of vitamin D, exerts immunologic activities on multiple components of the innate and adaptive immune system as well as endothelial membrane stability. Association between low levels of serum 25-hydroxyvitamin D and increased risk of developing several immune-related diseases and disorders, including psoriasis, type 1 diabetes, multiple sclerosis, rheumatoid arthritis, tuberculosis, sepsis, respiratory infection, and COVID-19, has been observed. Accordingly, a number of clinical trials aiming to determine the efficacy of administration of vitamin D and its metabolites for treatment of these diseases have been conducted with variable outcomes. Interestingly, recent evidence suggests that some individuals might benefit from vitamin D more or less than others as high inter-individual difference in broad gene expression in human peripheral blood mononuclear cells in response to vitamin D supplementation has been observed. Although it is still debatable what level of serum 25-hydroxyvitamin D is optimal, it is advisable to increase vitamin D intake and have sensible sunlight exposure to maintain serum 25-hydroxyvitamin D at least 30 ng/mL (75 nmol/L), and preferably at 40–60 ng/mL (100–150 nmol/L) to achieve the optimal overall health benefits of vitamin D.

Implications of Monsoon Season & UVB Radiation for COVID-19 in India Manuscript

“…, an active form of vitamin D, plays a critical role in the modulation of innate as well as adaptive immune systems 32,33 , renin-angiotensin system (RAS) [33][34][35] as well as in the modulation of the inflammatory response, reducing cytokine storm risk 32,33 . It also stimulates antimicrobial peptides such as defensins and human cathelicidin 32,33,36,37 with antiviral properties. Recent studies related to COVID-19 also indicate that vitamin D deficiency might be a risk factor not only for incidence 2,3 , but also for severity 4 5 and mortality [6][7][8] associated with COVID-19.…”

Vitamin D Deficiency and Outcome of COVID-19 Patients

“…The active form of vitamin D3, 1α, 25-dihydroxyvitamin D3 (1,25D3), also known as calcitriol, is a pluripotent hormone and important modulator of both innate and adaptive immunity [5], and serum total 25-hydroxyvitamin D (25(OH)D) is commonly used to assess individual vitamin D (VitD) status [6].…”

Zinc and Vitamin a Deficiency Predisposes to the Need for Intubation and Icu Admission in Patients With COVID-19. An Observational Study

“…Vitamin D would also have an antiviral effect, as well as a positive effect on immunity, modulating T and B cells, and also regulating the expression and secretion of cytokines such as TNF or IL-6. Low levels of serum vitamin D are linked to the occurrence of sepsis, as well as increased morbidity, mortality, and prolonged length of stay in the ICU in septic and critically ill patients [38]. This vitamin also has an anticoagulant effect, inversely correlated with D-dimer.…”