Vitamin D And The Immune System

Vitamin D Antigen Presentation And Innate Immunity

Effective management of infection not only involves adequate innate immune management of intracellular bacteria but also requires appropriate adaptive or acquired immune activity. At the interface between these two mechanisms are antigen-presenting cells, which present bacterial antigens to cells from the adaptive immune system such as T-lymphocytes . Macrophages are able to fulfil this function, but antigen presentation is more effectively executed by dendritic cells . It was recognised many years ago that DC isolated from lymphoid tissue express VDR, indicating that they were a likely target for vitamin D-mediated immunoregulation. This was confirmed by studies showing that treatment with 1,252D suppressed DC maturation and thereby promoted a tolerogenic phenotype. This effect was more pronounced in myeloid DC relative to plasmacytoid DC, despite both subsets expressing similar levels of VDR. Under steady state conditions myeloid DC are more active at priming naive T-cell responses. By contrast plasmacytoid DC exhibit more tolerogenic, immunosuppressive properties. Consequently, 1,252D appears to fulfil a more tolerogenic function by suppressing activity of myeloid DC, while leaving the already tolerogenic plasmacytoid DC unaffected.

Why Is Vitamin D Important To Our Immunity

Picture a female gymnast performing on the balance beam which is only four inches wide. The key word there is balance. Unless the gymnast is perfectly balanced while performing her extraordinary athletic moves while atop the beam, she risks falling off either side of the beam, losing points and possibly getting injured, sometimes severely.

Your immune system operates in a similar manner, always having to be perfectly balanced to function optimally. But it is also a complex system in terms of vitamin Ds role, per pharmacytimes.com, making such balance all the more delicate a proposition.

Vitamin D And Protective Immunity

Vitamin D has been used to treat infections such as tuberculosis before the advent of effective antibiotics. Tuberculosis patients were sent to sanatoriums where treatment included exposure to sunlight which was thought to directly kill the tuberculosis. Cod liver oil, a rich source of vitamin D has also been employed as a treatment for tuberculosis as well as for general increased protection from infections.

Results of studies looking at potential benefits of administering vitamin D to decrease infection have not been consistent, most likely secondary to a number of methodologic concerns. One recent well-designed prospective, double blind placebo study using an objective outcome, nasopharyngeal swab culture , and a therapeutic dose of vitamin D showed that vitamin D administration resulted in a statistically significant decrease in the incidence of influenza infection.

The beneficial effects of vitamin D on protective immunity are due in part to its effects on the innate immune system. It is known that macrophages recognize lipopolysacharide LPS, a surrogate for bacterial infection, through toll like receptors . Engagement of TLRs leads to a cascade of events that produce peptides with potent bacterialcidal activity such as cathelocidin and beta defensin 4. These peptides colocalize within phagosomes with injested bacteria where they disrupt bacterial cell membranes and have potent anti-microbacterial activity .

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Vitamin D And Rheumatoid Arthritis

In addition to inhibiting inflammatory cytokines such as IL-6, TNF, IL-17 in synovial fluid, vitamin D also reduces fibroblast erosion . Vitamin D supplementation was found to be associated with lower risk of RA in a prospective cohort of 29,368 women over a follow up period of 11 years . A randomized controlled trial by Buondonno et al. evaluated the effect of administration of cholecalciferol on T helper cell sub-types and osteoclast precursors. Single dose of cholecalciferol along with standard treatment showed improvements in inflammatory cytokines in this study . Further studies are required to estimate the dose of Vitamin D in the treatment of RA.

Food Sources Of Vitamin D

“Vitamin D naturally occurs in egg yolks, beef liver, fatty fish like salmon, tuna, swordfish or sardines and fish liver oils. Unfortunately, vitamin D isn’t naturally occurring in lots of foods, which is why some foods have vitamin D added to them. Vitamin D is added to cereals, dairy and plant milks and orange juice,” Tolentino says.

Even though you can get vitamin D from food, it’s difficult to get enough from that source on its own since the amount of vitamin D in most foods is pretty small. “It’s not that easy to get your daily recommended intake of vitamin D through food. We’re just not eating large quantities of most of these foods. How much beef liver or sardines are you realistically eating every day?” Tolentino says.

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Obtaining Vitamin D From Light Allows Your Body To Self

Obtaining vitamin D from light allows your body to self-regulate vitamin D production and make as much as it needs to stay healthy, without any risk of overdose or toxicity. Unlike with oral supplements, you cannot overdose on vitamin D3 produced by your skin. If you have enough vitamin D, your body will simply produce less.

In Vivo Immunomodulatory Properties Of 125

The in vivo use of 1,25-dihydroxyvitamin D3 and analogues

To evaluate their applicability in a more clinically relevant situation, such as the treatment of pre-diabetic patients with established insulitis, analogues of 1,252D3 were administered to NOD mice when autoimmune -cell destruction is already taking place. Treatment with different 1,252D3 analogues, either alone or in combination with a short induction course of cyclosporin A, blocks diabetes progression in NOD mice suffering from insulitisReference Casteels, Mathieu, Waer, Valckx, Overbergh, Laureys and Bouillon73,Reference Gregori, Giarratana, Smiroldo, Uskokovic and Adorini110.

Nowadays, pancreatic islet transplantation has proven to be an effective therapy in patients with type 1 diabetesReference Shapiro, Lakey, Ryan, Korbutt, Toth, Warnock, Kneteman and Rajotte116. However, strong immunosuppression is needed to prevent, besides allorejection, also the autoimmune destruction of transplanted islets by self-reactive memory T cells and thus diabetes recurrence. In NOD mice, treatment with a 1,252D3 analogue can prevent autoimmune diabetes recurrence after syngeneic islet transplantationReference Mathieu, Laureys, Waer and Bouillon117,Reference Casteels, Waer, Laureys, Valckx, Depovere, Bouillon and Mathieu118.

Combined immunotherapy

1,25-Dihydroxyvitamin D3 and infection

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Vitamin D And Immunologic Function

Vitamin D has numerous effects on cells within the immune system. It inhibits B cell proliferation and blocks B cell differentiation and immunoglobulin secretion. Vitamin D additionally suppresses T cell proliferation and results in a shift from a Th1 to a Th2 phenotype. Furthermore, it affects T cell maturation with a skewing away from the inflammatory Th17 phenotype and facilitates the induction of T regulatory cells. These effects result in decreased production of inflammatory cytokines with increased production of anti-inflammatory cytokines such as IL-10 . Vitamin D also has effects on monocytes and dendritic cells . It inhibits monocyte production of inflammatory cytokines such as IL-1, IL-6, IL-8, IL-12 and TNF. It additionally inhibits DC differentiation and maturation with preservation of an immature phenotype as evidenced by a decreased expression of MHC class II molecules, co-stimulatory molecules and IL12 .

Vitamin D Reduces Immune Cell Activity

Researchers at the University of Edinburgh looked at how vitamin D affects two types of cells, called dendritic cells and T cells. These cells are both part of our immune system.

Normally, dendritic cells activate T cells, which play an important role in fighting infections. But in MS, these T cells attack the bodys own tissues leading to the damage associated with MS.

These results, , suggest that low levels of vitamin D may lead to more T cell activation and therefore an increased immune response. This could influence the risk of autoimmune conditions like MS.

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Functional Medicine And Vitamin D

Integrative medicine supports the use of vitamin D in the pursuit of optimal health, and the functional benefits it provides. The growing prevalence of vitamin D deficiency affects not only patients with established risk factors, but those who have no risk factors and marginal insufficiency as well.

What Does A Closer Look At The Study Tell Us

The researchers reported that

• 123 people taking vitamin D developed autoimmune disease, compared with 155 people in the placebo group. This represents a 22% reduction. That sounds like a lot, but the actual decrease in risk for developing an autoimmune disease fell from about 12 people in 1,000 to 9.5 people in 1,000.
• Rheumatoid arthritis, polymyalgia rheumatica, and psoriasis were the most common conditions. No single autoimmune disease was reliably prevented by vitamin D supplementation. Only when the numbers of all the autoimmune diseases were combined did researchers see a benefit.
• The benefit of vitamin D was more obvious when only the final three years of the study were analyzed. This suggests that it takes a while to benefit from a daily supplement.
• Those assigned to receive omega-3 fatty acids did not have a lower risk for confirmed autoimmune disease.
• Side effects were minor and similar in those taking supplements and those taking placebo.

This randomized study is among the best to explore the impact of vitamin D supplementation on the risk of developing autoimmune disease. Yet the study relied on self-reported cases, later confirmed by medical record review. So its possible that some cases of autoimmune disease were overlooked.

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Where Can I Find Other People’s Reviews Of The Form Of Vitamin D For Immune System

There are many benefits to reading other people’s reviews of the product that you’re considering buying. Not only does it provide you with an unbiased opinion, but it also gives you a sense of how someone else might feel about the product.

There are countless websites where users can post their honest opinions and thoughts on products they’ve used or seen in person these sites can be found by performing a basic internet search for product review website or user review site.

Be sure to check out these websites before making your final purchase decision!

Reviews are one of the best sources for making a buying decision. It’s always helpful to see what other people think about products before buying them, and reviews can be found on the Internet.

If you’re looking specifically for reviews on a particular product, try searching Google or YouTube to find out which site has more thoughts on that specific topic.

You might also want to look at places like Amazon or Yelp if they have enough information about your desired item.

Nuclear Receptors For Vitamin Metabolites

Locally produced 1,252VD3 can act on immune cells in an autocrine or paracrine manner. On complexing with 1,252VD3, the nuclear vitamin D receptor heterodimerizes with nuclear receptors of the retinoic X receptor family which has three main isoforms: , and and binds to VD3 response elements in the promoters of VD3-responsive genes .

Similarly, retinoic acid exerts its multiple effects by binding to nuclear receptors of the retinoic acid receptor family, which also has three main isoforms: , and . These form RARRXR heterodimers, which interact with retinoic acid response elements within the promoters of retinoic acid-responsive genes11,12. RAR proteins are ubiquitously expressed and are also upregulated by retinoic acid11,12. As mentioned above, RXR proteins can also pair with VDR proteins or form RXRRXR homodimers, which are specific receptors for 9-cis-retinoic acid but not for all-trans retinoic acid . In addition, RXR proteins are partners for other nuclear receptors, such as thyroid hormone receptor, peroxisome proliferator-activated receptor and liver X receptor, among others17. Therefore, it is possible that, given their common RXR nuclear binding partners, some ligands, such as 1,252VD3 and retinoic acid, might antagonize each others effects18.

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Vitamin D And Immune Health

Research shows that vitamin D plays an important role in immune function, and a deficiency in it is shown to increase your susceptibility to infection. “Some studies have shown that vitamin D deficiency is even associated with greater risk of self-reported upper respiratory tract infections,” Tolentino says. Further, “low serum levels of calcidiol are also associated with higher susceptibility to infections like tuberculosis, influenza, and viral infections of the upper respiratory tract,” Tolentino says.

One of the main functions of vitamin D is to help activate T cells, aka the “killer cells” in the body. T cells actually detect and destroy foreign pathogens — like viruses. “That makes vitamin D especially crucial for maintaining a functioning immune system that’s capable of fighting back foreign pathogens,” Tolentino says.

It’s important to know that although the coronavirus does affect the respiratory system, researchers and doctors know little about how vitamin D affects your risk of catching COVID-19 at this time. The best ways to reduce your risk of being infected with the coronavirus is to follow CDC and WHO guidelines, what your local officials say and to take care of your health as much as you can overall. Vitamin D is known to help the immune system, which is promising for protecting you from many different types of illness.

Exposing your skin to the sun is one way to get vitamin D.

Vitamin D And The Adaptive Immune System

The expression of the nuclear VDR and vitamin D-activating enzymes in both T- and B types of human adaptive immune cells have been reported in studies. The activation and proliferation of T and B cells results in up-regulation of VDR expression, which ultimately regulates more than 500 vitamin D responsive genes .

Following are the proposed mechanisms for influence of vitamin D on T cell function :

All these effects of vitamin D result in shifting from a proinflammatory status to a more tolerogenic immune status, including very diverse effects on T cell subtypes: Vitamin D suppresses T helper cell proliferation, differentiation and modulates synthesis of cytokines .

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Vitamins D2 And D3 Do Not Influence Expression Of The Same Genes In Whole Blood

Excluding genes that were also differentially expressed over the 12-week intervention in the placebo group, only 13% of down-regulated differentially expressed genes were common between the two treatment groups while 28% and 59% were uniquely down-regulated by vitamins D2 and D3, respectively . For example, some biological processes such as histone modification and covalent chromatin modification are downregulated following vitamin D3 supplementation only, while spliceosomal function are upregulated by vitamin D2 only. Functional categories of genes enriched among the upregulated genes, following supplementation with either vitamin D2 or D3, include translation, mitochondrial and spliceosome function statistically enriched biological cellular component terms in these functional categories are ribosomal proteins, components of the mitochondrial respiratory chain, two subunits of the histone H4 and snRNP Sm protein components of the spliceosome assembly. It is known that, in addition to influencing transcription, vitamin D can also influence post-transcriptional events by recruiting co-regulators . In this context it is relevant that components of the spliceosome, such as snRNP Sm proteins that mediate both transcriptional control and splicing decisions, leading to alternatively spliced transcripts , were upregulated by vitamin D supplementation in this study.

The Gastrointestinal Immune System

The unique features of the GI tract include a heterogenous mix of cells that are either absent or functionally different than immune cells in peripheral tissues.

Epithelial cells:

Provides a physical barrier between the host and the luminal contents .

Produces tight junction proteins and secretes mucins and antimicrobial peptides .

Expresses pattern recognition receptors that identifies microbes .

Intraepithelial lymphocytes:

Most are T cells with very few B cells and myeloid cells .

Most of the T cells express CD8 which identifies the T cells as regulatory cells. The T cells that express CD8 can also express CD4 or CD8.

High frequency of T cells and CD8+ T cells.

Lamina propria:

Dendritic cells and specialized CD103+ dendritic cells. The expression of CD103+ on dendritic cells reduces the ability of the dendritic cells to activate T cells .

Conventional CD4 cells: Th1, Th2, Th17 cells and conventional CD8 T cells.

Innate lymphoid cells that produce IL-22 .

Regulatory T cells that recognize commensal microbes, FoxP3+/RORt+ T reg .

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Can Vitamins Boost Your Immune System

Your immune system works tirelessly to fight off any harmful bacteria and viruses that you come into contact with. Its one of the most complicated and interconnected systems in the human body, with many different factors shaping your immune response. These include your genetic makeup, age, health status and stress levels.

Diet is one of the biggest contributors to a healthy immune system. A growing body of evidence suggests that the modern Western diet high in sugar, salt and fat may be to blame for a steep rise in chronic diseases across the world.

Your body needs an array of different nutrients to power up your defences and stay free from disease. But while certain nutrients do a good job in supporting the immune system, its not as easy as just popping a multivitamin pill every morning. If youre serious about improving your immunity, you may need to implement lasting and far-reaching changes to your dietary habits.

Still, addressing vitamin and mineral deficiencies could be a good start. Micronutrients contribute to the bodys natural defences by strengthening its physical barriers , increasing the production of antibodies and improving communication between cells. Some vitamins tend to be better at supporting your immune system than others too.