Evaluation of a 12-week targeted vitamin D supplementation regimen in patients with active inflammatory bowel disease

Impact of Vitamins, Antibiotics, Probiotics, and History of COVID-19 on the Gut Microbiome in Ulcerative Colitis Patients: A Cross-Sectional Study

Background and Objectives: The human gut microbiome is essential for the health of the host and is affected by antibiotics and coronavirus disease 2019 (COVID-19). The gut microbiome is recognized as a contributing factor in the development of ulcerative colitis. Specific vitamins and probiotics have been demonstrated to positively influence the microbiome by enhancing the prevalence of expected beneficial microorganisms. Materials and Methods: Forty-nine ulcerative colitis (UC) outpatients from Riga East Clinical University Hospital were enrolled in this cross-sectional study from June 2021 to December 2021. All patients were divided into groups based on history of COVID-19 (COVID-19 positive vs. COVID-19 negative) in the last six months. Information about antibiotic, probiotic, and vitamin intake were outlined, and faecal samples were collected. The MetaPhlAn v.2.6.0 tool was used for the taxonomic classification of the gut microbiome metagenome data. Statistical analysis was performed using R 4.2.1. Results: Of the 49 patients enrolled, 31 (63%) were male and 18 (37%) were female. Coronavirus disease 2019 was found in 14 (28.6%) patients in the last 6 months. Verrucomicrobia was statistically significantly lower in the COVID-19 positive group (M = 0.05; SD = 0.11) compared to the COVID-19 negative group (M = 0.5; SD = 1.22), p = 0.03. Antibiotic non-users had more Firmicutes in their microbiome than antibiotic users (p = 0.008). The most used vitamin supplement was vitamin D (N = 18), fifteen (42.9%) of the patients were COVID-19 negative and 3 (21.4%) were COVID-19 positive over the last six months (p > 0.05). Vitamin C users had more Firmicutes in their gut microbiome compared to non-users (Md = 72.8 [IQR: 66.6; 78.7] vs. Md = 60.1 [IQR: 42.4; 67.7]), p = 0.01. Conclusions: Antibiotic non-users had more Firmicutes than antibiotic users in their gut microbiome. Only vitamin C had statistically significant results; in users, more Firmicutes were observed. A mild course of COVID-19 may not influence ulcerative colitis patients' gut microbiome.

The Colonic Vitamin D Receptor and Inflammatory Bowel Disease: No Correlation to Histologic or Endoscopic Inflammation

The role of the vitamin D receptor (VDR) in inflammatory bowel disease (IBD) is poorly described. The aim of this study was to examine the relationship between immunohistochemical VDR expression and IBD activity. The immunohistochemical expression of VDR was analysed in biopsies from active and inactive IBD in 28 patients (ulcerative colitis: 21, Crohn's disease: 7) and 12 non-IBD controls. VDR expression did not change in active compared to inactive disease (p = 0.40 in epithelium and p = 0.29 in stroma). There was a trend for higher VDR expression in controls compared to IBD patients. No relationship was found between VDR expression and histologic inflammation (r = -0.19, p = 0.89 for epithelium and r = 0.13, p = 0.35 for stroma), colonoscopic picture and clinical and laboratory measures including serum 25(OH) vitamin D status (r = -0.91, p = 0.82). IBD disease activity did not correlate to VDR immunohistochemical expression, nor did it differ compared to controls. These results partly conflict with prior studies, but these have only shown modest correlations. Prospective studies investigating VDR activity between IBD and controls should be contemplated.

Effects of Vitamin D-3 Supplementation During Pregnancy and Lactation on Maternal and Infant Biomarkers of Environmental Enteric Dysfunction, Systemic Inflammation, and Growth: A Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Environmental enteric dysfunction (EED) is an acquired, subclinical state of intestinal inflammation common in children and adults in low-income and middle-income countries. Although vitamin D-3 supplementation has purported anti-inflammatory properties, its ability to ameliorate biomarkers of EED remains unclear.

OBJECTIVES

This study aimed to examine the effects of maternal vitamin D-3 supplementation during pregnancy and lactation on biomarkers of EED, systemic inflammation, and growth in women living with HIV and their infants in Dar es Salaam, Tanzania.

METHODS

We conducted subgroup analyses among randomly selected mothers (n = 720) and infants (n = 365 at 6 wk of age, and n = 266 at 6 mo of age) who participated in a randomized, triple-blind, placebo-controlled trial of daily maternal 3000 IU vitamin D-3 supplementation from the second trimester of pregnancy until 1 y postpartum. Biomarkers of EED (soluble CD14 and intestinal fatty acid-binding protein), systemic inflammation (C-reactive protein and α1-acid glycoprotein), and growth factors (insulin-like growth factor 1 and fibroblast growth factor 21) were measured via the Micronutrient and Environmental Enteric Dysfunction Assessment Tool. Anti-flagellin and anti-lipopolysaccharide immunoglobulins were measured via enzyme-linked immunosorbent assay. Comparisons by randomized treatment arm were performed using ordinary least squares regression models with log2-transformed biomarkers.

RESULTS

At 32 wk of gestation, intestinal fatty acid-binding protein (β: -0.19; P = 0.03) and α1-acid glycoprotein (β:-0.11; P = 0.04) were significantly lower in mothers in the vitamin D-3 group than those in mothers in the placebo group. At 6 wk of age, insulin-like growth factor 1 (β:-0.31; P = 0.03) was significantly lower in infants whose mothers were in the vitamin D-3 group than that in infants whose mothers were in the placebo group.

CONCLUSIONS

Vitamin D-3 supplementation during pregnancy and lactation reduced selected EED and systemic inflammation biomarkers among women living with HIV. While the effects of maternal vitamin D-3 supplementation do not appear to extend to infants, there may be an effect on growth factors. This trial was registered at clinicaltrials.gov as NCT02305927 (https://clinicaltrials.gov/study/NCT02305927).

The use of vitamin D for patients with inflammatory bowel diseases

As vitamin D (VD) plays an essential role in inflammatory bowel diseases (IBD), this systematic review aimed to update the participation of this vitamin in the prevention or remission of these diseases. This review has included studies in MEDLINE-PubMed, EMBASE, and Cochrane databases. The authors have followed PRISMA (Preferred Reporting Items for a Systematic Review and Meta-analysis) guidelines. According to the inclusion and exclusion criteria, twenty-two randomized clinical trials were selected. In total, 1,209 patients were included in this systematic review: 1034 received only VD and 175 received VD in combination with calcium. The average doses of VD supplementation were from oral 400 IU daily to 10,000 IU per kilogram of body weight. Single injection of 300,000 IU of VD was also used. Several studies have shown the crucial role that VD plays in the therapeutic approach of IBD due to its effects on the immune system. It effectively decreased inflammatory cytokines such as TNF-α and IFN-γ (p<0.05) and provided a reduction in disease activity assessed through different scores such as Crohn's Disease Activity Index (CDAI) (p<0.05) and Ulcerative Colitis Disease Activity Index (UCDAI) (p<0.05). Unfortunately, the available clinical trials are not standardized for of doses and routes of administration. Existing meta-analyses are biased because they compare studies using different doses or treatments in combination with different drugs or supplements such as calcium. Even though VD has crucial effects on inflammatory processes, there is still a need for standardized studies to establish how the supplementation should be performed and the doses to be administered.

1,25(OH)2D3 alleviates oxidative stress and inflammation through up-regulating HMGCS2 in DSS-induced colitis

BACKGROUND

Previous study found that supplements with active vitamin D3 alleviated experimental colitis. The objective of this study was to investigate the possible role of 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), a ketone synthase, on vitamin D3 protecting against experimental colitis.

METHODS

HMGCS2 and vitamin D receptor (VDR) were measured in UC patients. The effects of vitamin D deficiency (VDD) and exogenous 1,25(OH)2D3 supplementation on experimental colitis were investigated in dextran sulfate sodium (DSS)-treated mice. DSS-induced oxidative stress and inflammation were analyzed in HT-29 cells. HMGCS2 was detected in 1,25(OH)2D3-pretreated HT-29 cells and mouse intestines. HMGCS2 was silenced to investigate the role of HMGCS2 in 1,25(OH)2D3 protecting against experimental colitis.

RESULTS

Intestinal HMGCS2 downregulation was positively correlated with VDR reduction in UC patients. The in vivo experiments showed that VDD exacerbated DSS-induced colitis. By contrast, 1,25(OH)2D3 supplementation ameliorated DSS-induced colon damage, oxidative stress and inflammation. HMGCS2 was up-regulated after 1,25(OH)2D3 supplementation both in vivo and in vitro. Transfection with HMGCS2-siRNA inhibited antioxidant and anti-inflammatory effects of 1,25(OH)2D3 in DSS-treated HT-29 cells.

CONCLUSION

1,25(OH)2D3 supplementation up-regulates HMGCS2, which is responsible for 1,25(OH)2D3-mediated protection against oxidative stress and inflammation in DSS-induced colitis. These findings provide a potential therapeutic strategy for alleviating colitis-associated oxidative stress and inflammation.

Infections and Autoimmunity-The Immune System and Vitamin D: A Systematic Review

Both 25-autoimmunity and(25(OH)D: calcifediol) and its active form, 1,25-dihydroxyvitamin D (1,25(OH)2D: calcitriol), play critical roles in protecting humans from invasive pathogens, reducing risks of autoimmunity, and maintaining health. Conversely, low 25(OH)D status increases susceptibility to infections and developing autoimmunity. This systematic review examines vitamin D's mechanisms and effects on enhancing innate and acquired immunity against microbes and preventing autoimmunity. The study evaluated the quality of evidence regarding biology, physiology, and aspects of human health on vitamin D related to infections and autoimmunity in peer-reviewed journal articles published in English. The search and analyses followed PRISMA guidelines. Data strongly suggested that maintaining serum 25(OH)D concentrations of more than 50 ng/mL is associated with significant risk reduction from viral and bacterial infections, sepsis, and autoimmunity. Most adequately powered, well-designed, randomized controlled trials with sufficient duration supported substantial benefits of vitamin D. Virtually all studies that failed to conclude benefits or were ambiguous had major study design errors. Treatment of vitamin D deficiency costs less than 0.01% of the cost of investigation of worsening comorbidities associated with hypovitaminosis D. Despite cost-benefits, the prevalence of vitamin D deficiency remains high worldwide. This was clear among those who died from COVID-19 in 2020/21-most had severe vitamin D deficiency. Yet, the lack of direction from health agencies and insurance companies on using vitamin D as an adjunct therapy is astonishing. Data confirmed that keeping an individual's serum 25(OH)D concentrations above 50 ng/mL (125 nmol/L) (and above 40 ng/mL in the population) reduces risks from community outbreaks, sepsis, and autoimmune disorders. Maintaining such concentrations in 97.5% of people is achievable through daily safe sun exposure (except in countries far from the equator during winter) or taking between 5000 and 8000 IU vitamin D supplements daily (average dose, for non-obese adults, ~70 to 90 IU/kg body weight). Those with gastrointestinal malabsorption, obesity, or on medications that increase the catabolism of vitamin D and a few other specific disorders require much higher intake. This systematic review evaluates non-classical actions of vitamin D, with particular emphasis on infection and autoimmunity related to the immune system.

Immunomodulatory actions of vitamin D in various immune-related disorders: a comprehensive review

For many years, vitamin D has been acknowledged for its role in maintaining calcium and phosphate balance. However, in recent years, research has assessed its immunomodulatory role and come up with conflicting conclusions. Because the vitamin D receptor is expressed in a variety of immune cell types, study into the precise role of this molecule in diseases, notably autoimmune disorders, has been made possible. The physiologically activated version of vitamin D also promotes a tolerogenic immunological condition in addition to modulating innate and acquired immune cell responses. According to a number of recent studies, this important micronutrient plays a complex role in numerous biochemical pathways in the immune system and disorders that are associated with them. Research in this field is still relatively new, and some studies claim that patients with severe autoimmune illnesses frequently have vitamin D deficiencies or insufficiencies. This review seeks to clarify the most recent research on vitamin D's immune system-related roles, including the pathophysiology of major disorders.

British Dietetic Association consensus guidelines on the nutritional assessment and dietary management of patients with inflammatory bowel disease

BACKGROUND

Despite increased awareness of diet and nutrition being integral to the management of patients with inflammatory bowel disease (IBD), there are gaps in the knowledge of IBD healthcare providers regarding nutrition. Furthermore, high quality evidence on nutritional assessment and dietary management of IBD is limited. A Delphi consensus from a panel of experts allows for best-practice guidelines to be developed, especially where high quality evidence is limited. The aim was to develop guidelines for the nutritional assessment and dietary management of IBD using an eDelphi online consensus agreement platform.

METHODS

Seventeen research topics related to IBD and nutrition were systematically reviewed. Searches in Cochrane, Embase®, Medline® and Scopus® electronic databases were performed. GRADE was used to develop recommendations. Experts from the IBD community (healthcare professionals and patients with IBD) were invited to vote anonymously on the recommendations in a custom-built online platform. Three rounds of voting were carried out with updated iterations of the recommendations and evaluative text based on feedback from the previous round.

RESULTS

From 23,824 non-duplicated papers, 167 were critically appraised. Fifty-five participants completed three rounds of voting and 14 GRADE statements and 42 practice statements achieved 80% consensus. Comprehensive guidance related to nutrition assessment, nutrition screening and dietary management is provided.

CONCLUSIONS

Guidelines on the nutritional assessment and dietary management of IBD have been developed using evidence-based consensus to improve equality of care. The statements and practice statements developed demonstrate the level of agreement and the quality and strength of the guidelines.

Nutrition in inflammatory bowel diseases; Is there a role?

Nutrition is of paramount importance not only for healthy individuals, but all the more for the ones with pathologies interlinked with the diet. In that light, diet, when used accordingly can act in a protective manner in inflammatory bowel diseases. The interplay of diet and IBD is not thoroughly defined, and guidelines are a work in progress. However, significant knowledge has been gained with regard to foods and nutrients that may exacerbate or alleviate the core symptoms. Patients with IBD restrict from their diet a plethora of foods often arbitrary, thus depriving themselves from valuable constituents. Careful navigation into the newfound field of genetic variants and personalization of diet should be employed with avoidance of the Westernized diet, processed foods and additives, and focus on a holistic approach with a balanced diet rich in bioactive compounds in order to improve the quality of life of these patients and address diet-related deficiencies.

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.

Could the Majority of the Greek and Cypriot Population Be Vitamin D Deficient?

OBJECTIVE

Hypovitaminosis D is prevalent in epidemic proportions in many developed countries. The aim of this study is to investigate the prevalence of adequate 25-hydroxyvitamin D [25(OH)D] levels in two Mediterranean countries, Greece and Cyprus.

METHODS

Data such as 25(OH)D, the month of blood sample collection, and demographic information were blindly collected from 8780 Greek and 2594 Cypriot individuals over 5 years. Comorbidities were also recorded for 839 Greek subjects. Univariate and multivariate analyses were used to examine the relationship between these variables and 25(OH)D levels.

RESULTS

In the samples studied, 72.7% of the Greek and 69.3% of the Cypriot population sample had inadequate levels of 25(OH)D. The mean level for the Greek subjects was 25.1 ng/mL and for Cypriots 25.8 ng/mL. For both samples, only month and gender were significantly associated with 25(OH)D levels, and the highest mean levels were recorded in September. For the recorded diseases, the lowest levels were recorded in sickle cell anaemia 13.6 ± 10.2 ng/mL, autoimmune diseases 13.0 ± 8.4 ng/mL, and cancer 22.6 ± 9.5 ng/mL.

CONCLUSIONS

The prevalence of vitamin D deficiency is paradoxically high in both Mediterranean countries.

Complementary and Alternative Medicine in Crohn's Disease

Complementary and alternative medicine (CAM) is a growing entity within inflammatory bowel disease (IBD). CAM includes mind-based therapies, body-based therapies, supplements, vitamins, and probiotics. Limitations currently exist for health care providers as it pertains to IBD and CAM that stem from knowledge gaps, conflicting reports, limited oversight, and a lack of well-organized clinical data. Even without well-described data, patients are turning to these forms of therapy at increasing rates. It is imperative that the ongoing review of CAM therapies is performed, and future trials are performed to better understand efficacy as well as adverse effects related to these therapies.

Hypocholesterolemia and Inflammatory Biomarkers Act as Predictors of Severe Vitamin D Deficiency in Patients With Crohn’s Disease: A Clinical Analysis of 862 Patients in China

Background

In this study, we enrolled 862 patients with Crohn’s disease (CD) in China to investigate the correlation between serum vitamin D (SVD) and serum lipids, inflammatory biomarkers, and important clinical parameters.

Materials and Methods

25(OH)D was measured by LS/MS/MS. Correlation analysis, chi-square tests, and logistic regression analysis were performed to determine the correlations between vitamin D and potential risk factors when vitamin D levels were lower than 10 ng/mL or 20 ng/mL.

Results

The incidence of severe vitamin D deficiency (SVD < 10 ng/mL) in patients with CD was significantly higher than that in healthy controls (28.9 vs. 9.5%). Multinomial logistic regression analysis showed that penetrating disease [odds ratio (OR) = 2.18], low levels of high-density lipoprotein cholesterol (HDL) (OR = 1.91), high erythrocyte sedimentation rate (OR = 1.73), and platelet count (PLT) (OR = 2.71) were regarded as predictors of severe vitamin D deficiency, while only PLT (OR = 1.90) and HDL (OR = 1.76) were considered as predictors of mild vitamin D deficiency (SVD 10–20 ng/mL).

Conclusion

Our results confirm a higher incidence of severe vitamin D deficiency in patients with CD in China and show that vitamin D deficiency could result from the combined effects of penetrating disease, inflammation, and low levels of HDL.

Role of vitamin D in ulcerative colitis: an update on basic research and therapeutic applications

INTRODUCTION

Vitamin D deficiency is common in patients with ulcerative colitis (UC). Moreover, vitamin D supplementation seems to contribute to disease relief. Nevertheless, the exact etiological link between vitamin D deficiency and UC is far from clear, and an agreement has not been reached on the frequency and dosage of vitamin D supplementation required.

AREAS COVERED

This review will outline the possible role of vitamin D in the pathogenesis of UC and summarize the current state of clinical research on vitamin D. Literature was searched on PUBMED, with 'Vitamin D,' 'Ulcerative colitis,' 'Vitamin D receptor,' and 'disease activity' as MeSH Terms. Relevant information is presented in figures or tables.

EXPERT OPINION

The etiological relationship between vitamin D and the onset of UC is still being researched. More high-quality double-blind randomized clinical studies are needed to determine the efficacy of vitamin D supplementation in the treatment of UC, whether as the main treatment or as an adjuvant treatment. Importantly, determining the dosage and frequency of vitamin D supplementation should be the main research direction in the future, and regional factors should also be fully considered in this respect.

Vitamin D in Inflammatory Bowel Diseases. Mechanisms of Action and Therapeutic Implications

(1) Background: Vitamin D is an immunoregulatory factor influencing intestinal homeostasis. Recent evidence supports a central role of this micronutrient in the course of Inflammatory Bowel Diseases (IBD). This narrative review aims to provide a general overview of the possible biological mechanisms of action of vitamin D and its therapeutic implications in IBD. (2) Methods: A systematic electronic search of the English literature up to October 2021 was performed using Medline and the Cochrane Library. Only papers written in English that analyzed the role of vitamin D in IBD were included. (3) Results: In vitro and animal studies reported that vitamin D signaling improves epithelial barrier integrity regulating the expression of several junctional proteins, defensins, and mucins, modulates the inflammatory response, and affects gut microbiome composition. Recent studies also suggest that vitamin D deficiency is highly prevalent among IBD patients and that low serum levels correlate with disease activity and, less clearly, with disease course. (4) Conclusions: An increasing body of evidence suggests some role of vitamin D in the pathophysiology of IBD, nonetheless the underlying mechanisms have been so far only partially elucidated. A strong correlation with disease activity has been reported but its implication in the treatment is still undefined. Thus, studies focused on this issue, the definition of vitamin D levels responsible for clinical effects, and the potential role of vitamin D as a therapeutic agent are strongly encouraged.

High-Dose Vitamin D Does Not Prevent Postoperative Recurrence of Crohn's Disease in a Randomized Placebo-Controlled Trial

BACKGROUND & AIMS

Vitamin D deficiency is common in Crohn's disease (CD). High-dose vitamin D had anti-inflammatory effects in preclinical studies and trials of patients with CD. We performed a randomized trial to determine whether high-dose vitamin D prevents postoperative recurrence of CD after ileocolonic resection.

METHODS

Patients with CD after ileocolonic resection with ileocolonic anastomosis were assigned randomly to groups given weekly 25,000 IU oral vitamin D (n = 72) or placebo (n = 71) for 26 weeks, at 17 hospitals in The Netherlands and Belgium, from February 2014 through June 2017. Patients were assessed at baseline and at weeks 2, 6, 12, and 26 for laboratory and clinical parameters, and underwent ileocolonoscopy at 26 weeks. The primary end point was endoscopic recurrence (modified Rutgeerts score, ≥i2b, as assessed by blinded readers) at 26 weeks. Secondary end points included clinical recurrence (Crohn's disease activity index, ≥220), quality of life (measured by the 36-Item Short Form Health Survey, Inflammatory Bowel Disease Questionnaire, and EuroQol, a 5-dimension questionnaire), and outcomes associated with the baseline serum concentration of vitamin D.

RESULTS

In the vitamin D group, serum levels of 25-hydroxy vitamin D increased from a median of 42 nmol/L at baseline to 81 nmol/L at week 26 (P < .00001), whereas levels did not change significantly in the placebo group and remained unchanged at 43 nmol/L. In the intention-to-treat analysis, the proportion of patients with endoscopic recurrence at 26 weeks did not differ significantly between the vitamin D vs the placebo group (58% vs 66%; P = .37). The cumulative rate of clinical recurrence did not differ significantly between the groups (18.1% in the vitamin D group vs 18.3% in the placebo group; P = .91). Quality of life improved slightly over time in both groups, but did not differ significantly between groups (P = .07). There were few adverse events in either group.

CONCLUSIONS

High-dose vitamin D, compared with placebo, did not reduce the incidence of postoperative endoscopic or clinical recurrence of CD in patients who underwent ileocolonic resection with ileocolonic anastomosis. ClinicalTrials.gov no: NCT02010762.

Vitamin D Modulates Intestinal Microbiota in Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is a chronic inflammation of the gastrointestinal tract (GIT), including Crohn's disease (CD) and ulcerative colitis (UC), which differ in the location and lesion extensions. Both diseases are associated with microbiota dysbiosis, with a reduced population of butyrate-producing species, abnormal inflammatory response, and micronutrient deficiency (e.g., vitamin D hypovitaminosis). Vitamin D (VitD) is involved in immune cell differentiation, gut microbiota modulation, gene transcription, and barrier integrity. Vitamin D receptor (VDR) regulates the biological actions of the active VitD (1α,25-dihydroxyvitamin D3), and is involved in the genetic, environmental, immune, and microbial aspects of IBD. VitD deficiency is correlated with disease activity and its administration targeting a concentration of 30 ng/mL may have the potential to reduce disease activity. Moreover, VDR regulates functions of T cells and Paneth cells and modulates release of antimicrobial peptides in gut microbiota-host interactions. Meanwhile, beneficial microbial metabolites, e.g., butyrate, upregulate the VDR signaling. In this review, we summarize the clinical progress and mechanism studies on VitD/VDR related to gut microbiota modulation in IBD. We also discuss epigenetics in IBD and the probiotic regulation of VDR. Furthermore, we discuss the existing challenges and future directions. There is a lack of well-designed clinical trials exploring the appropriate dose and the influence of gender, age, ethnicity, genetics, microbiome, and metabolic disorders in IBD subtypes. To move forward, we need well-designed therapeutic studies to examine whether enhanced vitamin D will restore functions of VDR and microbiome in inhibiting chronic inflammation.

[Inflammatory Bowel Disease and Vitamin D]

Vitamin D contributes to bone metabolism and acts as an immune modulator for both innate and adaptive immunity. The serum level of vitamin D has been associated with inflammatory diseases, such as inflammatory bowel disease (IBD). In epidemiologic studies, IBD patients have been shown to have low levels of vitamin D. The suboptimal circulating levels of vitamin D in IBD patients may be caused by low exposure to sunlight, dietary malabsorption, and the impaired conversion of active metabolites (1,25[OH]₂D). Recent studies have demonstrated that vitamin D deficiency in IBD can increase the chance of disease recurrence, IBD-related hospitalization or surgery, and deterioration of quality of life. Supplementation with vitamin D is therefore thought to reduce the risk of flare-ups and the improvement of the quality of life in IBD patients. This review aims to summarize the latest knowledge on the effects of vitamin D deficiency on IBD and the possible benefits of vitamin D supplementation in IBD patients.

Vitamin D Therapy in Adults With Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Vitamin D deficiency has been implicated in the pathogenesis of inflammatory bowel disease. Emerging literature suggests that optimization of vitamin D levels may be associated with improvements in disease activity and quality of life. We conducted a meta-analysis exploring the effect of vitamin D on serum 25-hydroxyvitamin D (s-25[OH]D) levels, clinical improvement, and biomarkers.

METHODS

MEDLINE, EMBASE, the Cochrane Library, and sources for grey literature were searched from inception until September 2019. The primary outcome was s-25(OH)D mean differences. Heterogeneity was assessed using the χ 2 test and the I2 statistic. Review Manager software v. 5.3 was used.

RESULTS

Twelve randomized controlled trials (n = 611) and 4 observational studies (n = 359) were included in the meta-analysis. On average, in the randomized controlled trials, vitamin D supplementation increased s-25(OH)D levels by 15.50 ng/mL (95% confidence interval [CI], 11.08-19.92, P ≤ 0.00001, I2 = 90%) and in observational studies they increased by 18.39 ng/mL (95% CI, 8.91-27.88, P = 0.0001, I2 = 82%). Subgroup analyses between vitamin D and placebo groups revealed that vitamin D increased s-25(OH)D by 14.85 ng/mL (95% CI, 9.96-19.73, P ≤ 0.00001, I2 = 90%) and when high doses of vitamin D were compared with low doses, high doses increased s-25(OH)D by 18.27 ng/mL (95% CI, 5.44-31.10, P = 0.005, I2 = 90%). The Harvey Bradshaw Index improved by -1.47 points (95% CI, -2.47 to -0.47, P = 0.004, I2 = 0%) and the high-sensitivity C-reactive protein decreased by -1.58 mg/L (95% CI, -2.95 to -0.21, P = 0.02, I2 = 0%).

CONCLUSIONS

Vitamin D supplementation in patients with IBD and vitamin D deficiency is effective at correcting vitamin D levels and is associated with improvement in clinical and biochemical disease activity scores.

Mucosal vitamin D signaling in inflammatory bowel disease

Epidemiological studies have identified vitamin D (25(OH)D) deficiency to be highly prevalent among patients with inflammatory bowel disease (IBD), and low serum levels correlate with a higher disease activity and a more complicated disease course. The link to IBD pathogenesis has been subject of investigations, primarily due to the distinct immunological functions of vitamin D signaling, including anti-inflammatory and anti-fibrotic actions. Vitamin D is a pleiotropic hormone that executes its actions on cells through the vitamin D receptor (VDR). A leaky gut, i.e. an insufficient intestinal epithelial barrier, is thought to be central for the pathogenesis of IBD, and emerging data support the concept that vitamin D/VDR signaling in intestinal epithelial cells (IECs) has an important role in controlling barrier integrity. Here we review the latest evidence on how vitamin D promotes the interplay between IECs, the gut microbiome, and immune cells and thereby regulate the intestinal immune response. On the cellular level, vitamin D signaling regulates tight junctional complexes, apoptosis, and autophagy, leading to increased epithelial barrier integrity, and promotes expression of antimicrobial peptides as part of its immunomodulating functions. Further, intestinal VDR expression is inversely correlated with the severity of inflammation in patients with IBD, which might compromise the positive effects of vitamin D signaling in patients with flaring disease. Efforts to reveal the role of vitamin D in the pathophysiology of IBD will pave the road for the invention of more rational treatment strategies of this debilitating disease in the future.

Editorial: low population mortality from COVID-19 in countries south of latitude 35 degrees North-supports vitamin D as a factor determining severity. Authors' reply

LINKED CONTENT This article is linked to Al‐Ani et al and Rhodes et al papers. To view these articles, visit https://doi.org/10.1111/apt.15779 and https://doi.org/10.1111/apt.15777.

Diminished Vitamin D Receptor Protein Levels in Crohn's Disease Fibroblasts: Effects of Vitamin D

Vitamin D (VD) deficiency has been associated to Crohn’s disease (CD) pathogenesis, and the exogenous administration of VD improves the course of the disease, but the mechanistic basis of these observations remains unknown. Vitamin D receptor (VDR) mediates most of the biological functions of this hormone, and we aim to analyze here the expression of VDR in intestinal tissue, epithelial cells, and fibroblasts from CD patients. The effects of VD on a fibroblast wound healing assay and murine intestinal fibrosis are also analyzed. Our data show diminished VDR protein levels in surgical resections and epithelial cells from CD patients. In intestinal fibroblasts isolated from damaged tissue of CD patients, we detected enhanced migration and decreased VDR expression compared with both fibroblasts from non-damaged tissue of the same CD patient or control fibroblasts. Treatment with VD increased VDR protein levels, avoided the accelerated migration in CD fibroblasts, and prevented murine intestinal fibrosis induced by the heterotopic transplant model. In conclusion, our study demonstrates diminished VDR protein levels associated with enhanced migration in intestinal fibroblasts from damaged tissue of CD patients. In these cells, VD accumulates VDR and normalizes migration, which supports that CD patients would benefit from the VD anti-fibrotic therapeutic value that we demonstrate in a murine experimental model.

Vitamin D Inhibits Pro-Inflammatory T Cell Function in Patients With Inflammatory Bowel Disease

BACKGROUND AND AIMS

Dysregulated T cell responses contribute to the pathogenesis of inflammatory bowel disease [IBD]. Because vitamin D [vitD] deficiency is a risk factor for adverse disease outcomes, we aimed to characterize the impact of vitD on intestinal and peripheral T cell profiles.

METHODS

T cells were isolated from peripheral blood and intestinal biopsies of IBD patients, incubated with vitD and characterized by flow cytometry. To translate these in vitro findings to the clinic, serum vitD concentrations and clinical outcomes were correlated with T cell phenotype and function in a prospective patient cohort.

RESULTS

Incubation of peripheral and intestinal T cells with 1,25(OH)2-vitD resulted in strongly reduced frequencies of pro-inflammatory CD4+ and CD8+ T cells producing interferon γ [IFNγ], interleukin-17 [IL-17], IL-22, IL-9 and tumour necrosis factor [TNF]. Univariable analysis of 200 IBD patients revealed associations of vitD deficiency with non-compliant vitD intake, season of the year and anaemia in Crohn's disease [CD] as well as disease activity in ulcerative colitis [UC]. Ex vivo immunophenotyping revealed that CD4+ and CD8+ T cell subsets were not substantially altered in vitD-deficient vs vitD-sufficient patients while regulatory T cell frequencies were reduced in UC and non-smoking CD patients with vitD deficiency. However, normalization of serum vitD concentrations in previously deficient CD patients resulted in significantly reduced frequencies of CD4+ T cells producing IFNγ, IL-17 and IL-22.

CONCLUSION

vitD exerts profound anti-inflammatory effects on peripheral and intestinal CD4+ and CD8+ T cells of IBD patients in vitro and inhibits TH1 and TH17 cytokine production in CD patients in vivo.

Skin Exposure to Narrow Band Ultraviolet (UVB) Light Modulates the Human Intestinal Microbiome

The recent worldwide rise in idiopathic immune and inflammatory diseases such as multiple sclerosis (MS) and inflammatory bowel diseases (IBD) has been linked to Western society-based changes in lifestyle and environment. These include decreased exposure to sunlight/UVB light and subsequent impairment in the production of vitamin D, as well as dysbiotic changes in the makeup of the gut microbiome. Despite their association, it is unclear if there are any direct links between UVB light and the gut microbiome. In this study we investigated whether exposing the skin to Narrow Band Ultraviolet B (NB-UVB) light to increase serum vitamin D levels would also modulate the makeup of the human intestinal microbiota. The effects of NB-UVB light were studied in a clinical pilot study using a healthy human female cohort (n = 21). Participants were divided into those that took vitamin D supplements throughout the winter prior to the start of the study (VDS+) and those who did not (VDS−). After three NB-UVB light exposures within the same week, the serum 25(OH)D levels of participants increased on average 7.3 nmol/L. The serum response was negatively correlated to the starting 25-hydroxy vitamin D [25(OH)D] serum concentration. Fecal microbiota composition analysis using 16S rRNA sequencing showed that exposure to NB-UVB significantly increased alpha and beta diversity in the VDS− group whereas there were no changes in the VDS+ group. Bacteria from several families were enriched in the VDS− group after the UVB exposures according to a Linear Discriminant Analysis (LDA) prediction, including Lachnospiracheae, Rikenellaceae, Desulfobacteraceae, Clostridiales vadinBB60 group, Clostridia Family XIII, Coriobacteriaceae, Marinifilaceae, and Ruminococcus. The serum 25(OH)D concentrations showed a correlation with the relative abundance of the Lachnospiraceae, specifically members of the Lachnopsira and Fusicatenibacter genera. This is the first study to show that humans with low 25(OH)D serum levels display overt changes in their intestinal microbiome in response to NB-UVB skin exposure and increases in 25(OH)D levels, suggesting the existence of a novel skin-gut axis that could be used to promote intestinal homeostasis and health.

Clinical Trial Registration:clinicaltrials.gov, NCT03962673. Registered 23 May 2019 – Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03962673?term=NCT03962673&rank=1.

Managing vitamin D deficiency in inflammatory bowel disease

Management of inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is generally cumbersome for patients and is a massive health-economic burden. In recent years, the immunomodulating effects of vitamin D have gained a huge interest in its possible pathogenic influence on the pathophysiology of IBD. Vitamin D deficiency is frequent among patients with IBD. Several clinical studies have pointed to a critical role for vitamin D in ameliorating disease outcomes. Although causation versus correlation unfortunately remains an overwhelming issue in the illusive chicken versus egg debate regarding vitamin D and IBD, here we summarise the latest knowledge of the immunological effects of vitamin D in IBD and recommend from available evidence that physicians regularly monitor serum 25(OH)D levels in patients with IBD. Moreover, we propose an algorithm for optimising vitamin D status in patients with IBD in clinical practice. Awaiting well-powered controlled clinical trials, we consider vitamin D supplementation to be an affordable and widely accessible therapeutic strategy to ameliorate IBD clinical outcomes.

Vitamin D deficiency associated with Crohn's disease and ulcerative colitis: a meta-analysis of 55 observational studies

PURPOSE

To investigate the association of serum levels of 25(OH)D and 1,25(OH)₂D₃ in healthy and non-healthy controls with Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

Three electronic databases: PubMed, EMbase and EBSCOhost CINAHL, were searched for observational studies to measure the relationship between serum levels of vitamin D (VitD) and CD (or UC).

RESULTS

Fifty-five studies were included in the meta-analysis. We found that mean serum 25(OH)D levels in patients with CD were significantly lower than those in healthy controls (MD: - 3.17 ng/mL; 95% CI - 4.42 to - 1.93). Results from the meta-analysis examining 1,25(OH)₂D₃ levels in Crohn's patients revealed higher levels in the CD group than in healthy (MD: 3.47 pg/mL; 95% CI - 7.72 to 14.66) and UC group (MD: 5.05 pg/mL; 95% CI - 2.42 to 12.52). Serum 25(OH)D levels were lower in the UC group than in the healthy control group (MD: - 2.52 ng/mL; 95% CI - 4.02 to - 1.02). In studies investigating the level of 1,25(OH)₂D₃ in UC and healthy control groups, the level of 1,25(OH)₂D₃ in the UC groups were found to be higher than that in the control groups (MD: 3.76 pg/mL; 95% CI - 8.36 to 15.57). However, the 1,25(OH)₂D₃ level in patients with UC was lower than that in CD groups (MD: - 6.71 pg/mL; 95% CI - 15.30 to 1.88). No significant difference was noted between CD patients and UC patients in terms of average serum 25(OH)D levels.

CONCLUSIONS

This study found that VitD levels were inversely related to CD and UC. Serum levels of 25(OH)D were lower in patients with CD and UC than in healthy people, and more than half of the patients had insufficient vitamin D levels. The serum level of 1,25(OH)₂D₃ in both the CD and UC groups was higher than that in healthy people.

Vitamin D in inflammatory bowel disease: From biology to clinical implications

Inflammatory bowel disease (IBD) is a chronic immune-mediated inflammatory disorder of the gastrointestinal tract consisting two principal categories, ulcerative colitis (UC) and Crohn's disease (CD). The precise etiology of IBD remains unknown. Vitamin D is an important micronutrient that plays a critical biological role in various processes in human tissues. However, the relationship between disruption of the gut microbiota and the development of IBD is unclear. Some studies suggest that IBD is the cause of disrupted gut microbiota while others propose that gut microbiota itself can lead to development of IBD. Regardless of this complexity, it has emerged that vitamin D is an immunoregulatory factor that plays a significant role in the pathogenesis of IBD by affecting the gut microbiome and the inflammatory response. It has been reported that 38.1% of CD patients and 31.6% of UC patients suffer from vitamin D deficiency (VDD). In this review, we aimed to evaluate the association between VDD and IBD, summarizing recent clinical studies examining the effect of low vitamin D and the role of vitamin D supplementation on IBD clinical outcomes.

European Crohn's and Colitis Organisation Topical Review on Complementary Medicine and Psychotherapy in Inflammatory Bowel Disease

Patients with inflammatory bowel disease [IBD] increasingly use alternative and complementary therapies, for which appropriate evidence is often lacking. It is estimated that up to half of all patients with IBD use various forms of complementary and alternative medicine during some point in their disease course. Considering the frequent use of such therapies, it is crucial that physicians and patients are informed about their efficacy and safety in order to provide guidance and evidence-based advice. Additionally, increasing evidence suggests that some psychotherapies and mind-body interventions may be beneficial in the management of IBD, but their best use remains a matter of research. Herein, we provide a comprehensive review of some of the most commonly used complementary, alternative and psychotherapy interventions in IBD.

Influence of Vitamin D Deficiency on Inflammatory Markers and Clinical Disease Activity in IBD Patients

Vitamin D has recently been discovered to be a potential immune modulator. Low serum vitamin D levels have been associated with risk of relapse and exacerbation of clinical outcomes in Crohn’s disease (CD) and ulcerative colitis (UC). A retrospective, longitudinal study was conducted to determine the association between vitamin D levels and inflammatory markers and clinical disease activity in inflammatory bowel disease (IBD). In addition, circulating 25(OH)D₃ progression was evaluated according to vitamin D supplementation. Participants were separated into three groups according to their vitamin D level: severe deficiency (SD), moderate deficiency (MD) and sufficiency (S). Serum 25(OH)D₃ was inversely correlated with faecal calprotectin (FC) for CD and UC but was only correlated with C-reactive protein (CRP) for UC patients. In the multivariate analysis of FC, CRP and fibrinogen (FBG), we predicted the presence of a patient in the SD group with 80% accuracy. A deficiency of 25(OH)D₃ was associated with increased hospitalisations, flare-ups, the use of steroids and escalating treatment. Supplemental doses of vitamin D were likely to be insufficient to reach adequate serum levels of 25(OH)D₃. Vitamin D intervention studies are warranted to determine whether giving higher doses of vitamin D in IBD might reduce intestinal inflammation or disease activity.

Serum vitamin D but not zinc levels are associated with different disease activity status in patients with inflammatory bowel disease

The incidence of inflammatory bowel disease (IBD) is increasing and the pathogenesis is still not completely understood. Micronutrients like vitamin D [25 (OH)D] and zinc play an important role in enzyme activities and the immune system. As the 25 (OH)D-receptor has been shown to be downregulated in patients with IBD, 25 (OH)D may emerge as a predictive marker for disease improvement. Studies on relationship of both micronutrients in IBD patients are lacking.We retrospectively evaluated serum levels of 25(OH)D and zinc together with baseline characteristics of 232 IBD patients. Uni- and multivariate analyses were performed for association between serum levels of 25(OH)D and zinc with clinical and deep remission (CR and DR).155 Crohn's disease (CD) and 77 ulcerative colitis (UC) patients were included. 54% (n = 125) and 6% (n = 14) of IBD patients showed deficient serum 25(OH)D levels below 20 ng/mL and zinc levels below 7 μmol/L. Serum 25(OH)D levels were significantly higher in IBD patients with CR (P = .02) and DR (P < .001) but not serum zinc levels, respectively. Serum 25(OH)D levels (P = .008), anti-tumor-necrosis-factor-α-trough-concentration (anti-TNF-α-TC) (P = .02) and CRP level (P = .02) were independently associated with CR in CD patients. Serum 25(OH)D threshold of 19 ng/mL discriminated CD patients with or without CR, having an area under the receiver operating curve analysis (AUROC) of 0.77 [95%-confidence interval (CI): 0.68-0.85]. In multivariate analysis serum 25(OH)D levels (P = .04) and anti-TNF-α-TC (P = .04) were associated with DR in CD patients. Serum 25(OH)D threshold of 26 ng/mL discriminated CD patients with or without DR, having an AUROC of 0.75 (95%-CI: 0.68-0.83).Serum 25(OH)D (P = .04) and fecal calprotectin levels (P = .04) were independently correlated with CR in UC patients. Serum 25(OH)D threshold of 32 ng/mL discriminated UC patients in CR with an AUROC of 0.83 (95%-CI: 0.71-0.95). Zinc levels did not correlate with disease activity status in CD or UC patients either.In conclusion, beside CRP and fecal calprotectin, serum 25(OH)D levels, but not serum zinc levels, may be an additional useful and noninvasive marker for characterizing different disease activity status of IBD patients. Measurement of serum 25(OH)D in IBD patients may be warranted. 25(OH)D supplementation in deficient IBD patients is recommended.

The Role of Vitamin D in Inflammatory Bowel Disease - Assessing Therapeutic and Preventive Potential of Supplementation and Food Fortification

Inflammatory bowel diseases are a group of chronic inflammatory conditions that affect gastrointestinal tract due to inapt and continuous immune activation in response to a myriad of predisposing factors (most notably genetics, environmental impact and gut microbiota composition). It has been shown that vitamin D status can also play a role in the disease pathogenesis, as its deficiency is commonly observed in two major forms of inflammatory bowel diseases - Crohn's disease and ulcerative colitis. Mounting evidence supports the concept of intricate relationship between gut dysbiosis and vitamin D metabolism, while suboptimal levels of this vitamin have been linked to increased clinical disease relapse rates, inadequate response to drugs, as well as decreased quality of life in patients with Crohn's disease and ulcerative colitis. Consequently, the pertinent question is whether increased vitamin D supplementation and (on a population level) food fortification may bring significant benefit to the affected individuals. In this short review we discuss the synthesis, functions, status and food sources of vitamin D, appraise biotechnological facets of vitamin D status analysis and food fortification, and concentrate on novel developments in the field that describe its influence on intestinal microbiota and inflammatory bowel disease.

The intestinal vitamin D receptor in inflammatory bowel disease: inverse correlation with inflammation but no relationship with circulating vitamin D status

BACKGROUND

The intestinal vitamin D receptor (VDR) remains poorly characterized in patients with inflammatory bowel disease (IBD).

METHODS

Colonoscopic biopsies and intestinal resection specimens from the terminal ileum, ascending and sigmoid colon, from patients with and without IBD, were analyzed for VDR mRNA quantification by polymerase chain reaction, and protein localization and semi-quantification by immunohistochemistry. The relationship between VDR and intestinal inflammation, serum 25(OH)D and oral vitamin D intake was elicited.

RESULTS

A total of 725 biopsies from 20 patients with Crohn's disease (CD), 15 with ulcerative colitis (UC) and 14 non-IBD controls who underwent colonoscopy were studied. VDR gene expression and protein staining intensity was similar across all three groups, and across the intestinal segments. Sigmoid colon VDR mRNA expression inversely correlated with faecal calprotectin (r = -0.64, p = 0.026) and histological score (r = -0.67, p = 0.006) in UC, and histological score (r = -0.58, p = 0.019) in patients with CD. VDR staining intensity was higher in quiescent than diseased segments. No relationship with serum 25(OH)D or oral vitamin D intake was noted. Immunohistochemical staining of 28 intestinal resection specimens from 15 patients (5 each with CD, UC and non-IBD controls) showed diffuse VDR staining in the mucosa, submucosa and circular muscle.

CONCLUSIONS

VDR transcript expression and protein staining intensity are inversely related to inflammation in IBD, but unrelated to serum 25(OH)D, and similar to non-IBD controls. Strategies to upregulate intestinal VDR, potentially translating to modulation of disease activity, require investigation.

Oral Nano Vitamin D Supplementation Reduces Disease Activity in Ulcerative Colitis: A Double-Blind Randomized Parallel Group Placebo-controlled Trial

INTRODUCTION

Vitamin D possesses anti-inflammatory properties and could be beneficial in ulcerative colitis (UC).

METHODS

We studied the effect of oral nano vitamin D3 supplementation on disease activity in active UC [ulcerative colitis disease activity index (UCDAI)≥3]. Patients with active UC and vitamin D <40 ng/mL were randomized to receive either oral nano vitamin D (60,000 IU/d×8 d) or placebo. They were evaluated for disease activity (UCDAI scores, C-reactive protein, erythrocyte sedimentation rate, and fecal calprotectin) at baseline and reassessed at 4 weeks. The response was defined as a 3-point reduction in UCDAI score at 4 weeks and reduction in inflammatory markers.

RESULTS

The median vitamin D levels increased from 15.4 to 40.83 mg/dL in vitamin D group (P≤0.001) and marginally from 13.45 to 18.85 mg/dL (P=0.027) in controls. The 3-point reduction in UCDAI was seen more often in vitamin D group as compared with the control (53% vs. 13%; P=0.001). Increase in vitamin D levels correlated with reduction in UCDAI score (P≤0.001; ρ=-0.713), C-reactive protein (P≤0.001; ρ=-0.603), and calprotectin (P=0.004; ρ=-0.368). Patients who achieved target vitamin D of >40 ng/mL (n=17) more often had a 3-point reduction in UCDAI (80% vs. 20%; P≤0.001) and reduction in grade of severity from 60% to 35% (P=0.038). Vitamin D administration (odds ratio, 9.17; 95% confidence interval, 2.02-41.67) and baseline histologic activity (odds ratio, 1.92; 95% confidence intervals, 1.2-3.08) independently predicted response.

CONCLUSIONS

Oral nano vitamin D supplementation in active UC is associated with a reduction in disease activity and severity grade and is seen more often in those who achieved a target vitamin D level of 40 ng/mL.

Vitamin D in Inflammatory Bowel Disease: Biological, Clinical and Therapeutic Aspects

BACKGROUND

Vitamin D has an immunoregulatory action in Inflammatory Bowel Disease (IBD) as well as other immune-mediated disorders. Its influence on intestinal permeability, innate and adaptive immunity, and the composition and diversity of the microbiota contribute to the maintenance of intestinal homeostasis. Patients with IBD have a greater prevalence of vitamin D deficiency than the general population, and a possible association between this deficit and a worse course of the disease. However, intervention studies in patients with IBD have proved inconclusive.

OBJECTIVE

To review all the evidence concerning the role of vitamin D as an important factor in the pathophysiology of IBD, review the associations found between its deficiency and the prognosis of the disease, and draw conclusions for the practical application from the main intervention studies undertaken.

METHODS

Structured search and review of basic, epidemiological, clinical and intervention studies evaluating the influence of vitamin D in IBD, following the basic principles of scientific data.

RESULTS

Vitamin D deficiency is associated with disease activity, quality of life, the consumption of social and healthcare resources, and the durability of anti-TNFα biological treatment. Determination of new metabolites of vitamin D, measurement of its absorption capacity and questionnaires about sun exposure could help identify groups of IBD patients with a special risk of vitamin D deficiency.

CONCLUSION

Well-designed intervention studies are needed in IBD, with probably higher objective plasma doses of vitamin D to establish its efficacy as a therapeutic agent with immunomodulatory properties. Meanwhile, vitamin D deficiency should be screened for and corrected in affected patients in order to achieve adequate bone and phosphocalcic metabolism.

High Prevalence of Vitamin D Deficiency among Patients with Inflammatory Bowel Disease

Background

Vitamin D is a hormone with immunomodulatory properties. Vitamin D deficiency has been reported for patients with inflammatory bowel disease (IBD). In this cross-sectional study, 25-hydroxyvitamin D3 (25-OH-D3) levels in patients with IBD were compared to those in patients with irritable bowel syndrome (IBS).

Methods

A total of 181 patients, 156 with IBD and 25 with IBS, were included. The influence of disease activity, inflammatory markers, physical activity, and season were assessed.

Results

A total of 58.6$ (n = 58) of the patients with Crohn's disease (CD) and 44.6$ (n = 25) of the patients with ulcerative colitis (UC) had a 25-OH-D3 level < 50 nmol/L. CD patients showed significantly decreased 25-OH-D3 levels compared to the IBS patients (p = 0.018), but no significant difference was found for UC patients. In a linear regression model adjusted for age, gender, and BMI, a significant inverse association of C-reactive protein (CRP) (p = 0.031) and faecal calprotectin (FC) (p = 0.025) with 25-OH-D3 levels was observed for CD patients. Seasonal variation in 25-OH-D3 levels was found in CD patients, with significantly lower values in spring than in summer (p = 0.04).

Conclusion

Vitamin D deficiency was common in all IBD patients, but more pronounced in CD patients, in whom it also showed a significant inverse association with inflammatory markers such as CRP and FC.

Vitamin D Deficiency in a Portuguese Cohort of Patients with Inflammatory Bowel Disease: Prevalence and Relation to Disease Activity

Background and Aims

Vitamin D deficiency is more common in inflammatory bowel disease (IBD) patients than in the general population. However, there are conflicting data about predictive factors of vitamin D deficiency and its potential association with disease activity. The aims of this study were to determine the prevalence and predictive factors of vitamin D deficiency and to evaluate a possible association with disease activity.

Methods

A prospective observational study was conducted, including patients with IBD from January to July 2016. The Endocrine Society guidelines were considered for defining levels of serum 25-hydroxyvitamin D (25-OH-D) as follows: deficient (< 20 ng/mL, < 10 ng/mL being severe deficiency), insufficient (21-29 ng/mL), and adequate (> 30 ng/mL).

Results

A total of 152 patients (52% men; 47.2 ± 17.3 years) were included, of whom 70% had Crohn's disease (CD). Thirty-seven percent of patients were on immunosuppressors and 17% were on biologics. The majority were outpatients (88.2%). Mean 25-OH-D levels were 17.1 ± 8 ng/mL (CD: 16.7 ± 8 ng/mL vs. ulcerative colitis: 17.6 ± 7 ng/mL, p = 0.1). Inadequate levels were present in 90.8% of patients (deficiency: 68.4%; insufficiency: 22.4%). A significant negative correlation between 25-OH-D levels and age (r = -0.2, p = 0.04), C-reactive protein (CRP) levels (r = -0.22, p = 0.004), and Harvey-Bradshaw index (HBi) (r = -0.32, p = 0.001) was found. Patients with severe deficiency showed a higher CRP (0.6 vs. 1.4 mg/dL, p = 0.03), erythrocyte sedimentation rate (ESR) (22 vs. 31 mm/h, p = 0.03), and HBi (2 vs. 5, p < 0.001) and lower hemoglobin (13.6 vs. 12.7 g/dL, p = 0.02). There was no association between vitamin D deficiency and gender, type, extent, and duration of disease, surgery, and other measures of disease activity, such as ESR, hemoglobin (these 2 items except for severe deficiency), fecal calprotectin, or Truelove and Witts classification.

Conclusions

There is a high prevalence of inadequate levels of vitamin D in IBD patients, particularly deficiency (68.4%). There seems to exist an association between lower levels of vitamin D and higher disease activity, especially in CD.

Associations between inflammatory bowel diseases and vitamin D

Inflammatory Bowel Diseases (IBD) are increasing sharply, and the common medications are not effective for most patients. Vitamin D (VD) has been considerate to reduce inflammatory processes and may be helpful in IBD. The aim of this review was to perform an update on the potential role of VD in the IBD. We performed a search for articles associating VD and IBD published in MEDLINE-PubMed and EMBASE. The focused question used for the search was "What is the association between Inflammatory Bowel Disease and Vitamin D?" The exclusion criteria for this search were studies not in English, editorials, case reports, or poster presentations. VD prevents the inflammatory process such as negatively interfering with the release of Interleukin (IL)-1, IL-6, and Tumour Necrosis Factor-α; enhancing the function of the intestinal epithelial barrier; decreasing the occurrence of apoptosis; stimulating Toll-Like Receptor-4; inducing the production of an antimicrobial peptide in Paneth cells. Furthermore, deficiency of VD is related to the severity of the symptoms and increased the risk of cancer and surgery. In conclusion, VD shows a potential role in the management of IBD, the supplementation is inexpensive, safe, and leads to improvement of the quality of life.

Vitamin D Axis in Inflammatory Bowel Diseases: Role, Current Uses and Future Perspectives

Increasing evidence supports the concept that the vitamin D axis possesses immunoregulatory functions, with vitamin D receptor (VDR) status representing the major determinant of vitamin D’s pleiotropic effects. Vitamin D promotes the production of anti-microbial peptides, including β-defensins and cathelicidins, the shift towards Th2 immune responses, and regulates autophagy and epithelial barrier integrity. Impairment of vitamin D-mediated pathways are associated with chronic inflammatory conditions, including inflammatory bowel diseases (IBD). Interestingly, inhibition of vitamin D pathways results in dysbiosis of the gut microbiome, which has mechanistically been implicated in the development of IBD. Herein, we explore the role of the vitamin D axis in immune-mediated diseases, with particular emphasis on its interplay with the gut microbiome in the pathogenesis of IBD. The potential clinical implications and therapeutic relevance of this interaction will also be discussed, including optimizing VDR function, both with vitamin D analogues and probiotics, which may represent a complementary approach to current IBD treatments.