Vitamin D and Autoimmune Diseases
The causes of autoimmune diseases are somewhat of a mystery. Ideally, the immune system – it runs at a “lukewarm” temperature – as it should, to keep viruses and other threats at bay, but not to be on overdrive. Of course, that’s the very problem with conditions like rheumatoid arthritis, ulcerative colitis, lupus, and multiple sclerosis – the body’s own defenses are set against itself.
It’s no secret that vitamin D can help boost the immune response, and help prevent illness (and protect bone density, cognitive health, and more) but is that a good thing where autoimmune diseases are concerned?
It turns out that vitamin D may be intricately connected to keeping our immune system in balance – not just boosting responses for the cold and flu season. That means that the risk or symptoms of rheumatoid arthritis may be reduced if vitamin D levels are at the proper levels – which is, admittedly, difficult to determine without a blood test.
Suffice to say, many people are deficient in vitamin D. If you work indoors or live in a northern climate, it is very likely that your blood levels of vitamin D are low. Other individuals have genetic predispositions to low vitamin D levels because of alterations in the vitamin D receptor (VDR) protein. And, anyone with autoimmune gastrointestinal diseases may simply have absorption issues with vitamin D. That’s why talking to a practitioner, getting vitamin D levels tested, and supplementing with vitamin D at therapeutic levels is an important step in balancing an immune response.
Illescas-Montes R, Melguizo-Rodríguez L, Ruiz C, Costela-Ruiz VJ. Vitamin D and autoimmune diseases. Life Sci. 2019 Sep 15;233:116744.
The prevalence of autoimmune diseases (ADs) has increased over the past few decades. Vitamin D deficiency is a common factor in many of these diseases, whose etiology remains poorly understood. The objective of this study was to review published data on the role of vitamin D in ADs. Vitamin D insufficiency has been described as an important factor in the development of some ADs, generally attributed to the key role of this vitamin in the immune system. Most studies show that adequate supplementation can prevent and improve the development of some of these diseases, although the optimal vitamin D dose remains controversial. We highlight the importance of measuring serum vitamin D levels of the population and developing strategies to improve and maintain levels with no health risks.
Yang CY, Leung PS, Adamopoulos IE, Gershwin ME. The implication of vitamin D and autoimmunity: a comprehensive review. Clin Rev Allergy Immunol. 2013;45(2):217–226.
Historically, vitamin D has been associated with the regulation of bone metabolism. However, increasing evidence demonstrates a strong association between vitamin D signaling and many biological processes that regulate immune responses. The discovery of the vitamin D receptor in multiple immune cell lineages, such as monocytes, dendritic cells, and activated T cells credits vitamin D with a novel role in modulating immunological functions and its subsequent role in the development or prevention of autoimmune diseases. In this review we, discuss five major areas in vitamin D biology of high immunological significance: (1) the metabolism of vitamin D; (2) the significance of vitamin D receptor polymorphisms in autoimmune diseases, such as multiple sclerosis, type 1 diabetes mellitus, and systemic lupus erythematosus; (3) vitamin D receptor transcriptional regulation of immune cell lineages, including Th1, Th17, Th2, regulatory T, and natural killer T cells; (4) the prevalence of vitamin D insufficiency/deficiency in patients with multiple sclerosis, type 1 diabetes mellitus, and systemic lupus erythematosus; and finally, (5) the therapeutic effects of vitamin D supplementation on disease severity and progression.
Altieri B, Muscogiuri G, Barrea L, Mathieu C, et al. Does vitamin D play a role in autoimmune endocrine disorders? A proof of concept. Rev Endocr Metab Disord. 2017;18(3):335-346.
In the last few years, more attention has been given to the "non-calcemic" effect of vitamin D. Several observational studies and meta-analyses demonstrated an association between circulating levels of vitamin D and outcome of many common diseases, including endocrine diseases, chronic diseases, cancer progression, and autoimmune diseases. In particular, cells of the immune system (B cells, T cells, and antigen presenting cells), due to the expression of 1α-hydroxylase (CYP27B1), are able to synthesize the active metabolite of vitamin D, which shows immunomodulatory properties. Moreover, the expression of the vitamin D receptor (VDR) in these cells suggests a local action of vitamin D in the immune response. These findings are supported by the correlation between the polymorphisms of the VDR or the CYP27B1 gene and the pathogenesis of several autoimmune diseases. Currently, the optimal plasma 25-hydroxyvitamin D concentration that is necessary to prevent or treat autoimmune diseases is still under debate. However, experimental studies in humans have suggested beneficial effects of vitamin D supplementation in reducing the severity of disease activity. In this review, we summarize the evidence regarding the role of vitamin D in the pathogenesis of autoimmune endocrine diseases, including type 1 diabetes mellitus, Addison's disease, Hashimoto's thyroiditis, Graves' disease and autoimmune polyendocrine syndromes. Furthermore, we discuss the supplementation with vitamin D to prevent or treat autoimmune diseases.