Vitamin D in pediatric gastrointestinal disease

Investigating Vitamin D-Binding Protein's Role in Childhood Health and Development

Vitamin D-binding protein (DBP), also known as Gc-globulin, is a protein that affects several physiological processes, including the transport and regulation of vitamin D metabolites. Genetic polymorphisms in the DBP gene have a significant impact on vitamin D levels and may have implications for disease risk. DBP polymorphisms are linked to differential immune responses, which could influence the onset of juvenile diseases. This narrative review examines the various roles of DBP, with a focus on bone health, immunological regulation, and lipid metabolism in children. Chronic disorders affected by DBP polymorphisms include bone abnormalities, autoimmune diseases, cardiovascular issues, childhood asthma, allergies, cystic fibrosis, acute liver failure, celiac disease, inflammatory bowel disease, and chronic kidney disease. Future research should focus on identifying the processes that underpin the many roles that DBP plays and developing customized therapeutics to improve health outcomes in the juvenile population.

Anti-tissue transglutaminase antibodies (TG2A) positivity and the risk of vitamin D deficiency among children - a cross-sectional study in the generation R cohort

BACKGROUND

Suboptimal vitamin D status is common in people with celiac disease (CeD), a disease that can be characterized by the presence of serum anti-tissue transglutaminase antibodies (TG2A) (i.e., TG2A positivity). To date, it remains unclear whether childhood TG2A positivity is associated with vitamin D status and how this potential association can be explained by other factors than malabsorption only, since vitamin D is mainly derived from exposure to sunlight. The aim of our study was therefore to assess whether childhood TG2A positivity is associated with vitamin D concentrations, and if so, to what extent this association can be explained by sociodemographic and lifestyle factors.

METHODS

This cross-sectional study was embedded in the Generation R Study, a population-based prospective cohort. We measured serum anti-tissue transglutaminase antibodies (TG2A) concentrations and serum 25-hydroxyvitamin D (25(OH)D) concentrations of 3994 children (median age of 5.9 years). Children with serum TG2A concentrations ≥ 7 U/mL were considered TG2A positive. To examine associations between TG2A positivity and 25(OH)D concentrations, we performed multivariable linear regression, adjusted for sociodemographic and lifestyle factors.

RESULTS

Vitamin D deficiency (serum 25(OH)D < 50 nmol/L) was found in 17 out of 54 TG2A positive children (31.5%), as compared to 1182 out of 3940 TG2A negative children (30.0%). Furthermore, TG2A positivity was not associated with 25(OH)D concentrations (β -2.20; 95% CI -9.72;5.33 for TG2A positive vs. TG2A negative children), and this did not change after adjustment for confounders (β -1.73, 95% CI -8.31;4.85).

CONCLUSIONS

Our findings suggest there is no association between TG2A positivity and suboptimal vitamin D status in the general pediatric population. However, the overall prevalence of vitamin D deficiency in both populations was high, suggesting that screening for vitamin D deficiency among children, regardless of TG2A positivity, would be beneficial to ensure early dietary intervention if needed.

Vitamin D and malabsorptive gastrointestinal conditions: A bidirectional relationship?

This paper is one of the outcomes of the 5th International Conference "Controversies in Vitamin D" held in Stresa, Italy from 15 to 18 September 2021 as part of a series of annual meetings which was started in 2017. The scope of these meetings is to discuss controversial issues about vitamin D. Publication of the outcomes of the meeting in international journals allows a wide sharing of the most recent data with the medical and academic community. Vitamin D and malabsorptive gastrointestinal conditions was one of the topics discussed at the meeting and focus of this paper. Participants to the meeting were invited to review available literature on selected issues related to vitamin D and gastrointestinal system and to present their topic to all participants with the aim to initiate a discussion on the main outcomes of which are reported in this document. The presentations were focused on the possible bidirectional relationship between vitamin D and gastrointestinal malabsorptive conditions such as celiac disease, inflammatory bowel diseases (IBDs) and bariatric surgery. In fact, on one hand the impact of these conditions on vitamin D status was examined and on the other hand the possible role of hypovitaminosis D on pathophysiology and clinical course of these conditions was also evaluated. All examined malabsorptive conditions severely impair vitamin D status. Since vitamin D has known positive effects on bone this in turn may contribute to negative skeletal outcomes including reduced bone mineral density, and increased risk of fracture which may be mitigated by vitamin D supplementation. Due to the immune and metabolic extra-skeletal effects there is the possibility that low levels of vitamin D may negatively impact on the underlying gastrointestinal conditions worsening its clinical course or counteracting the effect of treatment. Therefore, vitamin D status assessment and supplementation should be routinely considered in all patients affected by these conditions. This concept is strengthened by the existence of a possible bidirectional relationship through which poor vitamin D status may negatively impact on clinical course of underlying disease. Sufficient elements are available to estimate the desired threshold vitamin D level above which a favourable impact on the skeleton in these conditions may be obtained. On the other hand, ad hoc controlled clinical trials are needed to better define this threshold for obtaining a positive effect of vitamin D supplementation on occurrence and clinical course of malabsorptive gastrointestinal diseases.

The Crosstalk between Vitamin D and Pediatric Digestive Disorders

Vitamin D is a cyclopentane polyhydrophenanthrene compound involved mainly in bone health and calcium metabolism but also autophagy, modulation of the gut microbiota, cell proliferation, immune functions and intestinal barrier integrity. The sources of vitamin D include sunlight, diet and vitamin D supplements. Vitamin D3, the most effective vitamin D isoform is produced in the human epidermis as a result of sunlight exposure. Vitamin D undergoes two hydroxylation reactions in the liver and kidney to reach its active form, 1,25-dihydroxyvitamin D. Recent studies highlighted a complex spectrum of roles regarding the wellbeing of the gastrointestinal tract. Based on its antimicrobial effect, it was recently indicated that vitamin D supplementation in addition to standard eradication therapy might enhance H. pylori eradication rates. Moreover, it was suggested that low levels of vitamin D might also be involved in the acquisition of H. pylori infection. In terms of celiac disease, the negative effects of vitamin D deficiency might begin even during intrauterine life in the setting of maternal deficiency. Moreover, vitamin D is strongly related to the integrity of the gut barrier, which represents the core of the pathophysiology of celiac disease onset, in addition to being correlated with the histological findings of disease severity. The relationship between vitamin D and cystic fibrosis is supported by the involvement of this micronutrient in preserving lung function by clearing airway inflammation and preventing pathogen airway colonization. Moreover, this micronutrient might exert anticatabolic effects in CF patients. Inflammatory bowel disease patients also experience major benefits if they have a sufficient level of circulating vitamin D, proving its involvement in both induction and remission in these patients. The findings regarding the relationship between vitamin D, food allergies, diarrhea and constipation remain controversial, but vitamin D levels should be monitored in these patients in order to avoid hypo- and hypervitaminosis. Further studies are required to fill the remaining gaps in term of the complex impact of vitamin D on gastrointestinal homeostasis.

Basic anthropometry, micronutrients status and growth velocity of patients with early-onset inflammatory bowel disease: A prospective cohort study

BACKGROUND AND STUDY AIM

Failure of optimal growth and lack of appropriate weight gain are major nutritional problems in children with inflammatory bowel disease (IBD). Therefore, this study was designed to assess the nutritional and growth status of patients with very-early-onset IBD (VEO-IBD) before and after individual-based nutritional interventions.

PATIENTS AND METHODS

This prospective cohort study assessed the nutritional status of 30 pediatric patients with VEO-IBD by performing comprehensive clinical examinations and evaluating anthropometric and biochemical parameters. The latter included the initial evaluation of serum albumin, prealbumin, minerals, and 25-hydroxyvitamin D. A 24-month nutritional strategy was designed for each patient. Patients who completed the study were reassessed after 6 months and their growth rate was calculated 2 years later.

RESULTS

The initial assessment of malnutrition severity using the World Health Organization's z-score revealed that 36.7%, 43.3%, and 26.7% of the study group were underweight, stunted, and wasted, respectively. Among the study population, Crohn's disease has the highest prevalence. Almost all patients had micronutrient deficiencies (i.e., iron, calcium, zinc, magnesium, and vitamin D) and subnormal serum levels of nutritional markers (i.e., prealbumin and albumin). Six months after the intervention, a significant improvement in anthropometric and biochemical parameters was detected (p < 0.05); nevertheless, the calculated growth rate revealed a considerable decrease after 2 years.

CONCLUSION

The early detection of nutritional impairment in patients with VEO-IBD remains a major challenge. Therefore, nutritional support and constant monitoring of these patients are necessary to ensure the improvement in their nutritional status and achieve an acceptable growth rate. Furthermore, we found that prealbumin could be a good discriminative tool for screening malnutrition in such patients.

Effects of adherence to the Mediterranean diet in children and adolescents with irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder in children and adults, which increased over the past twenty years. The Mediterranean diet is a well-known diet full of antioxidants and anti-inflammatory ingredients.

AIM

To evaluate the safety, tolerability, and effects of adherence to the Mediterranean diet on disease patterns in children and adolescents with IBS.

METHODS

This prospective, cross-sectional case-controlled study included 100 consecutive IBS patients diagnosed according to Rome IV criteria, aged 12-18 years. Patients were subdivided into two groups (50 patients each); Group I received a Mediterranean diet, and Group II on their regular diet for six months. Besides IBS scores (IBS-SSS, IBS-QoL, and total score), different clinical and laboratory parameters were evaluated at the start and end of the study.

RESULTS

The Mediterranean diet was safe and well-tolerated in IBS patients. IBS children and adolescents with good adherence to the Mediterranean diet (KIDMED Score ≥ 8 points); group I showed significant improvement in IBS scores. IBS-SSS in the Mediterranean diet group was 237.2 ± 65 at the beginning of the study and decreased to 163.2 ± 33.8 at the end of the study (P < 0.001). It did not show a significant improvement in the group with a regular diet (248.3 ± 71.1 at the beginning of the study compared to 228.5 ± 54.3 at the study end with P < 0.05). The mean IBS-SSS in the Mediterranean diet group significantly improved compared with the group with a regular diet. Mean IBS-QoL in group I improved from 57.3 ± 12.9 at the start of the study to 72.4 ± 11.2 at the study end (P < 0.001) and significantly improved when compared to its level in group II at the study end (59.2 ± 12.7 with P < 0.001), while group II showed no significant improvement in IBS-QoL at the study end when compared to the beginning of the study (59.2 ± 11.7 with P >0.05). The mean total IBS score in group I became 28.8 ± 11.2 at the end of our study compared to 24.1 ± 10.4 at the start (P < 0.05) and significantly improved when compared to its level in group II at the end of the study (22.1 ± 12.5 with P < 0.05), while in group II, non-significant improvement in the total score at the end of our study compared to its mean level at the start of the study (22.8 ± 13.5 with P > 0.05).

CONCLUSION

The Mediterranean diet was safe and associated with significant improvement in IBS scores in children and adolescent patients with IBS.

Efficacy and Safety of High-dose Cholecalciferol in Patients With Inflammatory Bowel Disease Receiving Infliximab

OBJECTIVE

Vitamin D deficiency is prevalent in patients with inflammatory bowel disease (IBD). The goal of this study was to assess the efficacy and safety of high-dose, interval cholecalciferol administration in patients with IBD receiving infliximab.

METHODS

This prospective, longitudinal, open-label study enrolled pediatric and young adult patients with IBD and vitamin D deficiency. Subjects received 50,000 IU every 4 to 5 weeks (n = 11) or 100,000 IU every 6 to 8 weeks (n = 32) of oral cholecalciferol for 1 year. Dosing was directly observed and administered in conjunction with infliximab infusions. The primary endpoint was vitamin D sufficiency, defined as a 25-hydroxy-vitamin D (25-OHD) level ≥30 ng/mL.

RESULTS

Forty-three participants constituted the primary analysis population. 25-OHD levels reached steady-state after the third dose, and mean increases in 25-OHD levels were 8 vs. 4.5 ng/mL in the 100,000 IU vs. 50,000 IU treatment groups, respectively. Only 43.8% of patients receiving 100,000 IU and 18.2% of patients receiving 50,000 IU achieved sufficiency. There was no difference in the 25-OHD level responsiveness in patients with Crohn disease versus those with ulcerative colitis (P = 0.72). There was no correlation between 25-OHD levels and clinical disease activity in patients with Crohn disease (P = 0.85) or ulcerative colitis (P = 0.24).

CONCLUSIONS

Supplementation with cholecalciferol was well-tolerated and direct observation is a promising paradigm for ensuring compliance with therapy. Patients with IBD, however, appear to require high doses of cholecalciferol, with less than half of patients (37% overall) achieving vitamin D sufficiency. Additional studies are necessary to determine the optimal treatment regimens.

The Role of Cannabinoid Receptor Type 2 in the Bone Loss Associated With Pediatric Celiac Disease

OBJECTIVES

In this study, we investigated the role of the cannabinoid receptor type 2 (CB2) in the bone loss associated with celiac disease (CD) evaluating the effect of its pharmacological modulation on osteoclast activity. We previously demonstrated a significant association between the CB2 Q63R variant and CD, suggesting it as a possible disease biomarker. Moreover, CB2 stimulation is beneficial for reducing osteoclast activity in several bone pathologic conditions.

METHODS

In vitro osteoclasts (OCs) were differentiated from peripheral blood mononuclear cells of healthy donors, CD children at diagnosis and after 1 year of gluten-free diet (GFD) and characterized by real-time PCR and western blot for the expression of CB2 and specific osteoclastic markers, TRAP and Cathepsin K. TRAP assay and Bone Resorption assay were performed to evaluate osteoclast activity before and after 48 h exposure to CB2 selective drugs (JWH-133 and AM630) and Vitamin D.

RESULTS

We found in CD patients an osteoclast hyperactivation and low levels of CB2. CB2 stimulation with JWH-133 agonist is more effective than Vitamin D in reducing osteoclast activity whereas CB2 blockade with AM630 increases osteoclast activation. The anti-osteoporotic effect of JWH-133 decreases when used in co-treatment with vitamin D. GFD reduces osteoclast activity without restore CB2 expression.

CONCLUSIONS

CB2 could be a molecular marker to predict the risk of bone alterations in CD and a pharmacological target to reduce bone mass loss in patients who need a direct intervention on bone metabolism, in addition to the GFD.

Possible Role of Vitamin D in Celiac Disease Onset

Beside skeletal system maintenance and protection, possible extra-calcium roles of vitamin D have been recently described. In particular, studies have investigated possible roles of vitamin D as a key modulator of inflammation and immune mechanisms and of the intestinal mucosa barrier. In this regard, vitamin D has been considered as a factor that affects different conditions such as immune-mediated diseases. The new emerging role of vitamin D and its involvement in immune modulation has led it to be considered as a possible key factor involved in celiac disease (CD) onset. CD is a chronic immune-mediated enteropathy of the small intestine that is triggered by dietary gluten protein exposure in individuals who are genetically predisposed. However, along with gluten, other environmental factors are also involved in CD onset. The renewed interest in a molecule that offers great possibilities for new roles has led to an increase in studies, although there remains a lack of studies aimed at contextualizing the role of vitamin D on CD. This review aims to define the possible role of vitamin D in CD onset as it is presently understood, taking into account potential links among vitamin D, the immune system and CD.

The Immunomodulatory Role of Vitamin D in Respiratory Diseases

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The growing interest in the new role of vitamin D, particularly as an immunomodulatory factor, has spurred basic research and the development of clinical trials to better understand the influence of supplementation on various diseases. Vitamin D is an important nutrient factor in human health due to its role in calcium metabolism regulation, cellular growth, differentiation and its fundamental discovered activity in immune functions. It has influenced different diseases, particularly inflammatory and autoimmune diseases, through immune response regulation, modulating innate and adaptive immunity.

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The aim of this review was to explore the role of vitamin D in the main respiratory diseases in children such as asthma, chronic rhinosinusitis, cystic fibrosis and recurrent respiratory infections.

An Innovative Effective Nutritional Therapy for Vitamin D Deficiency in Children with Celiac Disease

Children with celiac disease (CD) are susceptible to reduced bone mineral density (BMD). Our target is to assess the severity of vitamin D deficiency in CD children on a gluten-free diet (GFD), and to evaluate the effectiveness of adding an innovative GF meal, on the clinical and bone biochemical indices of CD patients. 50 CD children who were diagnosed and followed up at Pediatric gastroenterology clinic, Specialized pediatric hospital, Cairo University; by serology and biopsy of the duodenum were included in this prospective study. CD children were on GFD for at least one year. As a control group, 40 healthy children were enrolled. Thorough clinical examination, anthropometric assessment, a complete history and 24 hours dietary recall were done for all the participants in this work. We introduced our innovative GF meal to CD patients twice/day, for 3 consecutive months. Venous blood samples were withdrawn from patients at the study beginning and after 3 months for detection of serum vitamin D, calcium, phosphorous and alkaline phosphatase levels. The anthropometric measurements, serum vitamin D, and calcium were markedly decreased in CD children than that of controls. In CD patients, a significant increase in anthropometric parameters, vitamin D and calcium were found. While there was a significant decline of serum alkaline phosphatase, and a slight decrease in serum phosphorus at the study end. The innovative gluten-free prepared meal confirmed to be of high nutritional value in the management of vitamin D deficiency and improvement of bone indices in CD patient.

Nutritional Deficiencies in Children with Celiac Disease Resulting from a Gluten-Free Diet: A Systematic Review

BACKGROUND

A strictly gluten-free diet (GFD) is the basis for managing celiac disease (CD). Numerous studies have reported nutritional deficiencies/imbalances ascribable to a GFD. The aim of this review is to describe nutritional deficiencies observed in children with celiac disease on a GFD, to discuss the clinical consequences related to these nutritional imbalances, and to identify strategies that may be adopted to treat them.

METHODS

We reviewed the MEDLINE and EMBASE databases between January 1998 and January 2019.

RESULTS

Children are, regardless of whether they are on a gluten-free diet or not, at risk of consuming too much fat and insufficient fiber, iron, vitamin D, and calcium. These imbalances may be exacerbated when children are on a gluten-free diet. In particular, the intake of folate, magnesium, zinc, and foods with a high glycemic index in children with CD who are on a GFD is significantly altered.

CONCLUSIONS

Therapeutic protocols should include nutritional education to help teach subjects affected by disorders such as CD the importance of labels, the choice of foods, and the combination of macro- and micronutrients. Children with CD on a GFD should be encouraged to rotate pseudo-cereals, consume gluten-free commercial products that have been fortified or enriched, and use foods that are local and naturally gluten-free.

Association of the Vitamin D Level and Quality of School Life in Adolescents with Irritable Bowel Syndrome

There is no treatment of choice for irritable bowel syndrome, which affects up to 20% of school-aged children. This cross-sectional study evaluated the difference in the average vitamin D level between subtypes of irritable bowel syndrome, and the relationship between the vitamin D level as well as the severity of irritable bowel syndrome symptoms. We included 124 adolescents aged 10–17 years (68 boys, 56 girls; mean age 12.29 ± 1.92 years) from 2014 to 2016. Patients with irritable bowel syndrome were diagnosed by Rome III criteria and classified by clinical manifestation: irritable bowel syndrome with constipation (n = 29), irritable bowel syndrome with diarrhea (n = 63), and irritable bowel syndrome with constipation and diarrhea (n = 32). The severity of irritable bowel syndrome symptoms and school absence were evaluated. Vitamin D levels were measured by serum 25-hydroxyvitamin D. The chi-square test and analysis of variance were used. The patients’ average vitamin D level was 16.25 ± 6.58 ng/mL. There was a significant negative association of the 25-hydroxyvitamin D level with symptom severity and school absence (p = 0.022 and p < 0.001, respectively). Vitamin D supplementation could be considered as a choice of therapeutic method.

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

REVIEW OF CELIAC DISEASE PRESENTATION IN A PEDIATRIC TERTIARY CENTRE

ABSTRACT BACKGROUND: Celiac disease is an immune-mediated disorder with a multiform presentation and therefore a challenging diagnosis. OBJECTIVE: Our purpose is to identify the epidemiological, clinical, laboratory and histologic characteristics of children with celiac disease at diagnosis and on follow-up. METHODS: Children with previously established or newly diagnosed celiac disease, admitted in a tertiary centre in a two-year period (2014-2016) were recruited. Data was collected retrospectively from electronic medical records and clinical notes, and subsequently analysed with SPSS version 20.0. RESULTS: A total of 159 patients, out of 312, were included. Age ranged from 1 to 17 years (mean ± SD: 8.5±4.5 years, 69% girls). Disease presentation was classical in 60%, non-classical in 25%, subclinical in 10% and 5% classified as potential celiac disease. Non-classical and subclinical profiles had a higher mean age at presentation but not statistically significant (P-value 0.24). The most frequent gastrointestinal features at presentation were abdominal pain (58%), diarrhea (43%) and bloating (27%). A positive family history for celiac disease was present in 24% (n=35). We found anaemia in 23%, low ferritin in 63% and a moderate to severe deficiency of 25-hydroxyvitamin D in 62%. celiac disease -specific serologic testing and esophagogastroduodenoscopy were performed in 99%. Histology revealed modified Marsh 2 or 3 enteropathy in 94%, the remaining had normal histology but positive human leukocyte antigen typing. Clinical improvement at 12 months of gluten-free diet was complete in 51% and partial in 49%. IgA tTG normalized after 12-30 months of gluten-free diet in 45%. On growth assessment at diagnosis and after 12-28 months of gluten-free diet, 100% had height increase (mean ±SD: 7.11±4.43 cm) and 96% weight gain (mean ±SD: 5.60±4.91 kg). CONCLUSION: Our findings outline the diverse clinical presentations of pediatric celiac disease that should be considered irrespective of age. Increased clinician’s awareness will enable an early diagnosis and treatment, with subsequent symptom and nutritional status improvement.

Vitamin D supplementation in adolescents with irritable bowel syndrome: Is it useful? A randomized controlled trial

BACKGROUND/AIM

Vitamin D deficiency is common in irritable bowel syndrome (IBS). There is growing interest in the role of vitamin D in pediatric IBS. We aimed to evaluate the effect of vitamin D supplementation in adolescents with IBS and vitamin D deficiency.

PATIENTS AND METHODS

One hundred and twelve adolescents with IBS and vitamin D deficiency were randomly divided into two groups of matched age and sex. The first group received oral vitamin D₃ 2000IU/day for 6 months and the second group received placebo for 6 months. Vitamin D status as well as different IBS score systems (IBS-SSS, IBS-QoL, and total score) were evaluated before and 6 months after treatment.

RESULTS

IBS patients who received vitamin D supplementation for 6 months showed significant improvement in IBS-SSS (P < 0.001), IBS-QoL (P < 0.001), and total score (P = 0.02) compared to IBS placebo group. IBS patients treated with vitamin D showed two folds increase in their serum vitamin D levels (from 17.2 ± 1.3 to 39 ± 3.3) ng/ml with P < 0.001. While in the placebo group, their serum vitamin D levels were not significantly changed (P = 0.66). Vitamin D was tolerated well without any recorded adverse effects during the study period.

CONCLUSION

Vitamin D supplementation can be effective in treating adolescents with IBS and vitamin D deficiency.

Is Vitamin D Deficiency Implicated in Autonomic Dysfunction?

Dysautonomia, dysfunction of the autonomic nervous system, presents with heterogeneous clinical features from an imbalanced regulation of the sympathetic and parasympathetic nervous systems. Low Vitamin D levels can explain the heterogeneous clinical features of migraine headaches, cardiac and gastrointestinal dysfunction, and oxidative stress evident in dysautonomia patients. The role of Vitamin D in modulating pain sensitivity has been recently established. However, there is a lack of research and understanding regarding the association between Vitamin D deficiency and autonomic dysfunction. Vitamin D is a neuroactive hormone that modulates autonomic balance, regulating the sympathetic and parasympathetic nervous systems, and has multisystem benefits. The following review explores the literature and addresses the relationship between Vitamin D deficiency and autonomic dysfunction. Overall, this literature review implicates Vitamin D deficiency in autonomic dysfunction and elucidates the potential therapeutic role of Vitamin D in autonomic disorders. PubMed search was performed for English articles from 1996 to 2016. Following keywords: Vitamin D, autonomic dysfunction and orthostatic hypotension, Vitamin D receptor, migraine and traumatic brain injury, Vitamin D, cardiac and gastrointestinal disease, Vitamin D, glutathione, oxidative stress, and serotonin were included. Only articles reporting primary data relevant to the above question were included in the study.