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.

No abstract

Background/Aim: To investigate the effects of vitamin D 3 supplementation on gut microbiota. Patients and Methods: Twenty adults with vitamin D insufficiency/deficiency [25(OH)D <30 ng/ml] were enrolled and given 600, 4,000 or 10,000 IUs/day of oral vitamin D 3 . Stool samples were collected at baseline and 8 weeks for identifying gut microbiota using 16S rRNA gene amplification and sequencing. Results: Baseline serum 25(OH)D was associated with increased relative abundance of Akkermansia and decreased relative abundance of Porphyromonas (p<0.05). After the intervention, we observed a dose-dependent increase in relative abundance of Bacteroides with a significant difference between the 600 IUs and the 10,000 IUs groups (p=0.027), and Parabacteroides with a significant difference between the 600 IUs and the 4,000 IUs groups (p=0.039). Conclusion: Increased serum 25(OH)D was associated with increased beneficial bacteria and decreased pathogenic bacteria. A dose-dependent increase in bacteria associated with decreased inflammatory bowel disease activity was observed after vitamin D 3 supplementation. Patients and MethodsHealthy adults who had vitamin D insufficiency/deficiency [25(OH)D<30 ng/ml] were enrolled in a randomized, doubleblinded, investigator initiated, pilot study. This study investigated broad gene expression changes in peripheral blood mononuclear cells following vitamin D 3 supplementation of 600, 4,000 or 10,000 IU/day of vitamin D 3 , as previously described (11). The study was 551

Vitamin D is known not only for its importance for bone health, but also for its biologic activities on other many other organ systems. This is due to the presence of the vitamin D receptor (VDR) in various types of cells and tissues, including the skin, skeletal muscle, adipose tissue, endocrine pancreas, immune cells and blood vessels. Experimental studies have shown that vitamin D exerts several actions that are thought to be protective against COVID-19 infectivity and severity. These include the immunomodulatory effects on the innate and adaptive immune systems, the regulatory effects on renin-angiotensin-aldosterone-system in the kidneys and the lungs, and the protective effects against endothelial dysfunction and thrombosis. Prior to the COVID-19 pandemic, studies have shown that vitamin D supplementation is beneficial in protecting against risk of acquiring acute respiratory viral infection and may improve outcomes in sepsis and critically ill patients. There are a growing number of data connecting COVID-19 infectivity and severity with vitamin D status, suggesting a potential benefit of vitamin D supplementation for primary prevention or as an adjunctive treatment of COVID-19. Although the results from most ongoing randomized clinical trials aiming to prove the benefit of vitamin D supplementation for these purposes are still pending, there is no downside to increasing vitamin D intake and having 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 minimize the risk of COVID-19 infection and its severity.

Objective To determine the association between vitamin D status and morbidity and mortality in adult hospitalized COVID-19 patients Methods We performed a retrospective chart review study in COVID-19 patients aged ≥18 years old hospitalized at Boston University Medical Center between March 1 – August 4, 2020. All studied patients were tested positive for COVID-19 and had serum levels of 25-hydroxyvitamin D results measured within one year prior to the date of positive tests. Medical information was retrieved from the electronic medical record and were analyzed to determine the association between vitamin D status and hospital morbidity and mortality. Results Among the 287 patients, 100 (36%) patients were vitamin D-sufficient [25(OH)D >30 ng/mL] and 41 (14%) patients died during the hospitalization. Multivariate analysis in patients aged ≥65 years old revealed that vitamin D sufficiency [25(OH)D ≥30 ng/mL] was statistically significantly associated with decreased odds of death (adjusted OR 0.33, 95%CI, 0.12–0.94), acute respiratory distress syndrome (adjusted OR 0.22, 95%CI, 0.05–0.96), and severe sepsis/septic shock (adjusted OR 0.26, 95%CI, 0.08–0.88), after adjustement for potential confounders. Among patients with body mass index <30 kg/m 2 , vitamin D sufficiency was statistically significantly associated with a decreased odds of death (adjusted OR 0.18, 95%CI, 0.04–0.84). No significant association was found in the subgroups of patients aged <65 years old or BMI ≥30 kg/m 2 . Conclusion We revealed an independent association between vitamin D sufficiency defined by serum 25(OH)D ≥30 ng/mL and decreased risk of mortality from COVID-19 in elderly patients and patients without obesity.

Background/Aim: To assess the impact of vitamin D supplementation on genomic and metabolomic profiles and relate them to the individual's responsiveness to varying doses of vitamin D 3 . Patients and Methods: Healthy adults were given either 600, 4000 or 10,000 IUs vitamin D 3 /day for 6 months. Circulating parathyroid hormone (PTH), 25hydroxyvitamin D [25(OH)D], calcium, peripheral white blood cells broad gene expression and urine and serum metabolomic profiles were evaluated. Results: There was a dose-dependent effect of vitamin D supplementation on serum 25(OH)D, PTH and broad gene expression. Serum calcium levels remained normal for all study subjects and no untoward toxicity was observed. The metabolomic profiles were related to the genomic expression analysis. There were significant inter-individual effects on gene expression and metabolomic profile in response to the same dose of vitamin D 3 supplementation, despite similar changes in 25(OH)D and PTH concentrations. Conclusion: These results may help explain the variability observed in clinical trials regarding vitamin D's non-calcemic health benefits.

Vitamin D plays an important role in maintaining a healthy mineralized skeleton. It is also considered an immunomodulatory agent that regulates innate and adaptive immune systems. The aim of this narrative review is to provide general concepts of vitamin D for the skeletal and immune health, and to summarize the mechanistic, epidemiological, and clinical evidence on the relationship between vitamin D and rheumatic diseases. Multiple observational studies have demonstrated the association between a low level of serum 25-hydroxyvitamin D [25(OH)D] and the presence and severity of several rheumatic diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), spondyloarthropathies, and osteoarthritis (OA). Nevertheless, the specific benefits of vitamin D supplements for the treatment and prevention of rheumatic diseases are less accepted as the results from randomized clinical trials are inconsistent, although some conceivable benefits of vitamin D for the improvement of disease activity of RA, SLE, and OA have been demonstrated in meta-analyses. It is also possible that some individuals might benefit from vitamin D differently than others, as inter-individual difference in responsiveness to vitamin D supplementation has been observed in genomic studies. Although the optimal level of serum 25(OH)D is still debatable, it is advisable it is advisable that patients with rheumatic diseases should maintain a serum 25(OH)D level of at least 30 ng/mL (75 nmol/L) to prevent osteomalacia, secondary osteoporosis, and fracture, and possibly 40–60 ng/mL (100–150 nmol/L) to achieve maximal benefit from vitamin D for immune health and overall health.

No abstract