Besides its benefits to bone health, vitamin D plays an important role in the immune system. Previous studies have even shown that vitamin D may help prevent respiratory tract infections
Previous research does show that vitamin D plays a critical role in the immune system.
In fact, vitamin D deficiency may increase the risk of developing several types of bacterial and viral infections.
A number of studies have also found that supplementation with vitamin D may have protective effects against respiratory tract infections, although it's unknown if this applies to 2019-nCoV as well.
While a vitamin D deficiency may increase the risk of getting viral infections, and clinical trial are going on to verify it.
Vitamin D is probably most known for its role in calcium and its importance to bone health.
But research is finding more and more that vitamin D has important effects on the immune system.
For example, vitamin D can promote the development of certain proteins, such as cathelicidin and beta defensin 4, that have antimicrobial activity.
A deficiency of vitamin D can weaken the immune system, potentially increasing the body's susceptibility to infectious diseases such as coronavirus.
A vitamin D deficiency may impair the immune system and potentially increase the risk of infection.
Unfortunately, vitamin D deficiency is very common. According to some estimates, almost 50% of people worldwide do not get enough vitamin D.
The primary source of vitamin D is sunlight exposure, which causes a chemical reaction in your skin that produces vitamin D. Other sources include supplements and some types of food.
For this reason, people who do not get enough sun exposure are at risk for vitamin D deficiency. Some other risk factors include obesity, dark skin, and older age.
Vitamin D deficiency is a worldwide issue. Factors that can increase the risk of deficiency include limited sun exposure, obesity, dark skin, and older age.
Tuberculosis (TB) is a disease caused by an infection from a bacteria called Mycobacterium tuberculosis that mainly affects the lungs.
According to a few clinical trials, supplementation with vitamin D may reduce symptoms and improve the treatment of TB.
Overall, however, studies have revealed mixed results. It remains to be seen if vitamin D supplementation has a clinical effect on TB until more research is done.
Respiratory tract infections are a group of infectious diseases that affect the sinuses, throat, airways, or lungs. COVID-19, the disease that is caused by the new coronavirus, also belongs in this group.
Several large scientific reviews show that vitamin D supplementation may help prevent respiratory tract infections, including the common cold, the flu, and pneumonia.
However, the study participants had to take vitamin D on a consistent basis for at least 3 months before any protective effects were seen.
It's unknown if vitamin D supplementation will have the same protective effects against COVID-19.
Vitamin D supplementation has been shown to help prevent respiratory tract infections
Vitamin D may help prevent and treat certain types of infection.
Many people are deficient in vitamin D, especially those who have limited sun exposure. Those with low vitamin D may need to take supplements to increase their levels.
If your vitamin D levels are low, it probably makes sense to get them to a healthy range ideally with sun and if not supplements so that your immune system is as healthy as possible.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855046/ *
VITAMIN D FOR TREATMENT AND PREVENTION Of INFECTIOUS DISEASES: A SYSTEMATIC REVIEW OF RANDOMIZED CONTROLLED TRIALS
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3308600/ **
Vitamin D has long been recognized as essential to the skeletal system. Newer evidence suggests that it also plays a major role regulating the immune system, perhaps including immune responses to viral infection. Interventional and observational epidemiological studies provide evidence that vitamin D deficiency may confer increased risk of influenza and respiratory tract infection. Vitamin D deficiency is also prevalent among patients with HIV infection. Cell culture experiments support the thesis that vitamin D has direct anti-viral effects particularly against enveloped viruses. Though vitamin D's anti-viral mechanism has not been fully established, it may be linked to vitamin D's ability to up-regulate the anti-microbial peptides LL-37 and human beta defensin 2. Additional studies are necessary to fully elucidate the efficacy and mechanism of vitamin D as an anti-viral agent.
https://www.ncbi.nlm.nih.gov/pubmed/30614127 ** -
The interplay between vitamin D and viral infections
The pleiotropic role of vitamin D has been explored over the past decades and there is compelling evidence for an epidemiological association between poor vitamin D status and a variety of diseases. While the potential anti-viral effect of vitamin D has recently been described, the underlying mechanisms by which vitamin D deficiency could contribute to viral disease development remain poorly understood. The possible interactions between viral infections and vitamin D appear to be more complex than previously thought. Recent findings indicate a complex interplay between viral infections and vitamin D, including the induction of anti-viral state, functional immunoregulatory features, interaction with cellular and viral factors, induction of autophagy and apoptosis, and genetic and epigenetic alterations. While crosstalk between vitamin D and intracellular signalling pathways may provide an essential modulatory effect on viral gene transcription, the immunomodulatory effect of vitamin D on viral infections appears to be transient. The interplay between viral infections and vitamin D remains an intriguing concept, and the global imprint that vitamin D can have on the immune signature in the context of viral infections is an area of growing interest.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3686844/ *
Vitamin D and Respiratory Tract Infections: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5310969/ ** -
Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data
https://www.ncbi.nlm.nih.gov/pubmed/29102433 - *
Effect of vitamin D supplementation on non-skeletal disorders: a systematic review of meta-analyses and randomised trials. -
The main new finding highlighted by this systematic review is that vitamin D supplementation might help to prevent common upper respiratory tract infections and asthma exacerbations.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/ -
Vitamin D and the Immune System -
It is now clear that vitamin D has important roles in addition to its classic effects on calcium and bone homeostasis. As the vitamin D receptor is expressed on immune cells (B cells, T cells and antigen presenting cells) and these immunologic cells are all are capable of synthesizing the active vitamin D metabolite, vitamin D has the capability of acting in an autocrine manner in a local immunologic milieu. Vitamin D can modulate the innate and adaptive immune responses. Deficiency in vitamin D is associated with increased autoimmunity as well as an increased susceptibility to infection. As immune cells in autoimmune diseases are responsive to the ameliorative effects of vitamin D, the beneficial effects of supplementing vitamin D deficient individuals with autoimmune disease may extend beyond the effects on bone and calcium homeostasis.
https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/