Effects of Vitamin D Supplementation in Patients with Irritable Bowel Syndrome: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Clinical Toxicology of Vitamin D in Pediatrics: A Review and Case Reports

Intoxication of vitamin D is not a common case in pediatrics. Vitamin D supplements are sold as OTC drugs; however, there is a lack of public education about the permissible limits of vitamin D intake which may lead to vitamin D toxicity (VDT). This review aims to give insights to readers or practitioners about the clinical toxicology of vitamin D in pediatrics, which includes the mechanism of VDT, case reports, and the management of vitamin D poisoning. VDT refers to serum 25(OH)D levels, particularly when the level exceeds 100 ng/mL (250 nmol/L) or is defined as hypervitaminosis D. Hypercalcemia is a common condition of vitamin D toxicity. Vitamin D and its metabolites in moderate levels can induce hypercalcemia, as indicated by the elevation of osteoclastic bone resorption, the presence of calcium in renal tubules, intestinal calcium intake (through increased production of calcium-binding protein in enterocytes), and the decrease of parathyroid hormone synthesis. VDT in pediatrics can be managed by discontinuing vitamin D intake; using activated charcoal, furosemide, prednisone, and calcitonin; rehydration using intravenous sodium chloride 0.9%; and dextrose fluid therapy. It is important for parents to be more careful when providing vitamin D to their children.

Vitamin D improves irritable bowel syndrome symptoms: A meta-analysis

Background & aims

Approximately 5%-10% of the population in most geographical regions suffer from irritable bowel syndrome (IBS), which creates a significant burden on individual patients, their families, and society. Recent advances in IBS therapies have indicated that vitamin D supplementation is potential to relieve its symptoms, but evidence of this is lacking. This meta-analysis aimed to estimate the effect of vitamin D on gastrointestinal (GI) symptoms in IBS patients.

Methods

The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched from their inception to March 2022. Statistical analyses were performed with Stata 12.0 and Review Manager 5.4, and statistical significance was defined as P < 0.05. The pooled results are presented as weighted mean differences (WMD) and 95% confidence intervals (CI).

Results

The meta-analysis including 6 randomized controlled trials (RCT) with 572 patients found a significant difference in IBS symptom severity score (WMD, -34.88; 95% CI, -62.48 to -7.27; P = 0.013; random-effects model) but no significant difference in IBS quality of life score (WMD, 3.33; 95% CI, -5.12 to -11.77; P = 0.440; random-effects model).

Conclusions

Overall, IBS patients may benefit from vitamin D supplementation to reduce the GI symptoms.

Strategies for Producing Low FODMAPs Foodstuffs: Challenges and Perspectives

In recent years, there has been a growing interest in a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) as a promising therapeutic approach to reduce the symptoms associated with irritable bowel syndrome (IBS). Hence, the development of low FODMAPs products is an important challenge for the food industry, and among the various foodstuffs associated with the intake of FODMAPs, cereal-based products represent an issue. In fact, even if their content in FODMAPs is limited, their large use in diet can be an important factor in developing IBS symptoms. Several useful approaches have been developed to reduce the FODMAPs content in processed food products. Accurate ingredient selection, the use of enzymes or selected yeasts, and the use of fermentation steps carried out by specific lactic bacteria associated with the use of sourdough represent the technical approaches that have been investigated, alone or in combination, to reduce the FODMAPs content in cereal-based products. This review aims to give an overview of the technological and biotechnological strategies applicable to the formulation of low-FODMAPs products, specifically formulated for consumers affected by IBS. In particular, bread has been the foodstuff mainly investigated throughout the years, but information on other raw or processed products has also been reported. Furthermore, taking into account the required holistic approach for IBS symptoms management, in this review, the use of bioactive compounds that have a positive impact on reducing IBS symptoms as added ingredients in low-FODMAPs products is also discussed.

The efficacy of vitamin D supplementation for irritable bowel syndrome: narrow scope and GRADE miss-interpretation

We read the article by Haung et al. that pooled the effects of vitamin D on irritable bowel syndrome symptoms and associated quality of life. However, the current review suffers from some methodological errors: inadequate search strategy; the grading of recommendations assessment, development, and evaluation (GRADE) miss-assessment; and miss-interpretation. Accordingly, addressing the emphasized limitations will lead to more robust findings and conclusions.

The Role of Calcium, 25-Hydroxyvitamin D, and Parathyroid Hormone in Irritable Bowel Syndrome: A Bidirectional Two-Sample Mendelian Randomization Study

Several observational studies have indicated the potential associations among calcium, vitamin D (Vit-D), and irritable bowel syndrome (IBS). However, the causal relationship deduced from these studies is subject to residual confounding factors and reverse causation. Therefore, we aimed to explore the bidirectional causal effects among serum calcium, Vit-D, PTH, and IBS at the genetic level by a two-sample Mendelian randomization (MR) analysis of the datasets from IEU OpenGWAS database. Sensitivity analyses were performed to evaluate the robustness. The estimates were presented as odds ratios (ORs) with their 95% confidence intervals (CIs). The results of the inverse variance weighted method did not reveal any causal relationship between the genetically predisposed calcium (OR = 0.92, 95% CI: 0.80-1.06, p = 0.25) and Vit-D (OR = 0.99, 95% CI: 0.83-1.19, p = 0.94) level and the risk of IBS. The bidirectional analysis demonstrated that genetic predisposition to IBS was associated with a decreased level of PTH (beta: -0.19, 95%CI: -0.34 to -0.04, p = 0.01). In conclusion, the present study indicates no causal relationship between the serum calcium and Vit-D concentrations and the risk of IBS. The potential mechanisms via which IBS affects serum PTH need to be further investigated.

Association between irritable bowel syndrome and micronutrients: A systematic review

BACKGROUND AND AIM

Irritable bowel syndrome (IBS) is a highly prevalent disorder of gut brain interaction with a multifactorial etiology. Food trigger avoidance is common among individuals with IBS and exclusion diets are gaining popularity. However, recent guidelines on IBS management cautioned regarding the use of unsupervised dietary therapy with concerns of development of poor eating habits and even nutritional deficiencies. We aimed to review the available literature on the effect of habitual and exclusion diets on micronutrient status as well as the role of micronutrient supplementation in alleviating IBS symptoms.

METHODS

Four electronic databases (PubMed, Embase, Cochrane, Web of Science) were searched for articles that reported micronutrient data in patients with IBS. Serum micronutrient levels and dietary intake of micronutrients in patients with IBS were collected. The extracted data were tabulated and organized by micronutrient type to observe for trends.

RESULTS

Twenty-six articles were included in this systematic review (12 interventional and 14 observational studies). Studies showed that generally IBS subjects had lower levels of vitamin B2, vitamin D, calcium, and iron at baseline compared with non-IBS subjects. Studies also found that exclusion diets were associated with lower intake of micronutrients especially vitamin B1, B2, calcium, iron, and zinc. There was a lack of interventional studies on micronutrients.

CONCLUSION

Irritable bowel syndrome patients are at risk of developing multiple micronutrient deficiencies that may have both localized gastrointestinal as well as systemic effects. Dietary management of IBS patients should include a proper dietitian review to ensure nutritional adequacy where possible.

The Effect of Vitamin D Supplementation on the Severity of Symptoms and the Quality of Life in Irritable Bowel Syndrome Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Irritable bowel syndrome (IBS), a gastrointestinal disorder affecting 7–12% of the population, is characterized by abdominal pain, bloating, and alternating bowel patterns. Data on risk and protective influences have yielded conflicting evidence on the effects of alternative interventions, such as vitamin D. This review focuses on the effects of vitamin D on IBS. A systematic review and meta-analysis considered all articles published until 4 April 2022. The search for randomized controlled trials assessing vitamin D efficacy in IBS with outcomes, primary (Irritable Bowel Severity Scoring System (IBS-SSS)) and secondary (IBS quality of life (IBS-QoL) and serum level of calcifediol (25(OH)D)), was performed on six databases, Google Scholar, Web of Science, SCOPUS, EMBASE, PubMed (MEDLINE), and Cochrane Central Register of Controlled Trials. We included six trials with 616 patients. The pooled analysis found no difference between vitamin D and placebo in improving IBS-SSS (MD: −45.82 with 95% CI [−93.62, 1.98], p = 0.06). However, the pooled analysis favored vitamin D over placebo in improving the IBS-Qol (MD: 6.19 with 95% CI [0.35, 12.03], p = 0.04) and serum 25(OH)D (MD: 25.2 with 95% CI [18.41, 31.98], p = 0.00001). Therefore, further clinical trials are required to reach clinically applicable and generalizable findings.

Vitamin D supplementation for irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND AND AIM

Irritable bowel syndrome (IBS) is a prevalent and complex gastrointestinal disorder characterized by chronic abdominal pain and altered bowel habits. Observational studies have suggested a relationship between serum vitamin D levels and IBS symptoms. This systematic review and meta-analysis aimed to investigate the clinical effects of vitamin D supplementation on IBS symptom severity and quality of life (QoL) measures.

METHODS

Medline, Embase, Scopus, Web of Science, and The Cochrane Library databases were systematically searched. Data abstraction and quality assessment were conducted by four authors independently, and discrepancies were resolved through consensus from the senior author. Continuous data were pooled with standardized mean difference (SMD) using the DerSimonian and Laird's random-effects model. Sensitivity analysis by risk of bias and potentially "predatory" publication were performed as well.

RESULTS

A total of 685 patients across eight studies were included in the meta-analysis. Vitamin D supplementation significantly improved IBS symptom severity scale scores, with a SMD of -0.77 (95% confidence interval [CI] -1.47 to -0.07, P = 0.04, I²  = 91%). Improvements in IBS-QoL scores were also observed, albeit not statistically significant (SMD 0.54; 95% CI -0.34 to 1.41, P = 0.15, I²  = 87%). However, small sample sizes, a relatively young study population, limited ethnicities, and varied vitamin D dosing strategies across the studies were notable limitations.

CONCLUSIONS

Vitamin D supplementation could be part of our clinical armamentarium when managing IBS patients due to the potential efficacy and good safety profile. Further randomized, controlled trials are required to confirm the therapeutic effects.

Biomolecules from Plant Wastes Potentially Relevant in the Management of Irritable Bowel Syndrome and Co-Occurring Symptomatology

During and following the processing of a plant’s raw material, considerable amounts are wasted, composted, or redistributed in non-alimentary sectors for further use (for example, some forms of plant waste contribute to biofuel, bioethanol, or biomass production). However, many of these forms of waste still consist of critical bioactive compounds used in the food industry or medicine. Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. The primary treatment is based on symptomatology alleviation and controlled dietary management. Thus, this review aimed to describe the possible relevance of molecules residing in plant waste that can be used to manage IBS and co-occurring symptoms. Significant evidence was found that many forms of fruit, vegetable, and medicinal plant waste could be the source of some molecules that could be used to treat or prevent stool consistency and frequency impairments and abdominal pain, these being the main IBS symptoms. While many of these molecules could be recovered from plant waste during or following primary processing, the studies suggested that enriched food could offer efficient valorization and prevent further changes in properties or stability. In this way, root, stem, straw, leaf, fruit, and vegetable pomaces were found to consist of biomolecules that could modulate intestinal permeability, pain perception, and overall gastrointestinal digestive processes.

Vitamin D Supplementation and Mental Health in Inflammatory Bowel Diseases and Irritable Bowel Syndrome Patients: A Systematic Review

Inflammatory bowel diseases (IBDs) and irritable bowel syndrome (IBS) are associated with decreased quality of life and mental health problems. Among various approaches to supportive therapy that aims to improve mental health in affected individuals, vitamin D supplementation is considered to be an effective method which may also be beneficial in alleviating the symptoms during the course of IBDs and IBS. The aim of the present study was to conduct a systematic review of the literature presenting the data regarding the influence of vitamin D supplementation on mental health in adults with inflammatory and functional bowel diseases, including IBDs and IBS. This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (Registration number CRD42020155779). A systematic search of the PubMed and Web of Science databases was performed, and the intervention studies published until September 2021 were included. The human studies eligible to be included in the review should have described any intervention involving vitamin D as a supplement in a group of adult patients suffering from IBDs and/or IBS and should have assessed any component of mental health, but studies presenting the effects of combined supplementation of multiple nutrients were excluded. After eliminating the duplicates, a total of 8514 records were screened and assessed independently by two researchers. Further evaluation was carried out on the basis of title, abstract, and full text. Finally, 10 studies (four for IBDs and six for IBS) were selected for the current systematic review, and their quality was assessed using the Newcastle-Ottawa Scale (NOS). The studies analyzed the influence of various doses of vitamin D on bowel diseases, compared the results of vitamin D supplementation with placebo, or administered specific doses of vitamin D to obtain the required level in the blood. Supplementation was performed for at least 6 weeks. The analyzed mental health outcomes mainly included disease-specific quality of life/quality of life, anxiety, and depression. The majority of studies (including high-quality ones) confirmed the positive effect of vitamin D supplementation on the mental health of IBD and IBS patients, which was proven by all research works evaluating anxiety and depression and by the majority of research works evaluating quality of life. Although the studies followed different dosage regimens and supplementation protocols, the positive influence of vitamin D on mental health was found to be consistent. The number of studies on patients suffering from ulcerative colitis and the availability of trials randomized against the placebo group was low in the current review, which is considered to be a limitation of the present study and could also reflect the final outcome of the analysis. The conducted systematic review established the positive effect of vitamin D supplementation on the mental health of IBD and IBS patients, but this result requires further investigation, particularly in relation to other mental health outcomes.

Complementary and Alternative Medicine Therapies for Irritable Bowel Syndrome

Complementary and alternative medicine (CAM) is a term used to define a broad range of therapies, most commonly grouped into natural products, mind-body medicine, and traditional systems of medicine. Patients with irritable bowel syndrome (IBS) commonly use CAM therapies, although there are many barriers that may keep patients and providers from talking about a patient's CAM use. Despite limited quantity and quality of evidence of CAM for IBS, providers can better counsel patients on CAM use by understanding pitfalls related to CAM use and by learning what is known about CAM.

Dietary modulation of gut microbiota for the relief of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a frequently diagnosed gastrointestinal (GI) disorder characterized by recurrent abdominal pain, bloating, and changes in the stool form or frequency without any structural changes and overt inflammation. It is not a life-threatening condition but causes a considerable level of discomfort and distress. Among the many pathophysiologic factors, such as altered GI motility, visceral hypersensitivity, and low-grade mucosal inflammation, as well as other immunologic, psychologic, and genetic factors, gut microbiota imbalance (dysbiosis), which is frequently found in IBS, has been highlighted as an etiology of IBS. Dysbiosis may affect gut mucosal homeostasis, immune function, metabolic regulation, and even visceral motor function. As diet is shown to play a fundamental role in the gut microbiota profile, this review discusses the influence of diet on IBS occurring through the modulation of gut microbiota. Based on previous studies, it appears that dietary modulation of the gut microbiota may be effective for the alleviation of IBS symptoms and, also an effective IBS management strategy based on the underlying mechanism; especially because, IBS currently has no specific treatment owing to its uncertain etiology.

Vitamin D supplementation in people with IBS has no effect on symptom severity and quality of life: results of a randomised controlled trial

Purpose

Several small trials suggest a benefit of vitamin D supplementation in irritable bowel syndrome (IBS). The generalisability of these reports is limited by their design and scale. This study aimed to assess whether vitamin D supplementation improved IBS symptoms in a UK community setting.

Methods

This was a randomised, double-blind, placebo-controlled study. Participants were recruited from the community in winter months between December 2017 and March 2019. 135 participants received either vitamin D (3,000 IU p.d.) or placebo for 12 weeks. The primary outcome measure was change in IBS symptom severity; secondary outcomes included change in IBS-related quality of life.

Results

The participants were analysed on an intent-to-treat basis. 60% of participants were vitamin D deficient or insufficient at baseline. Although vitamin D levels increased in the intervention arm relative to placebo (45.1 ± 32.88 nmol/L vs 3.1 ± 26.15 nmol/L; p < 0.001). There was no difference in the change of IBS symptom severity between the active and placebo trial arms (− 62.5 ± 91.57 vs – 75.2 ± 84.35, p = 0.426) over time. Similarly there was no difference between trial arms in τhe change in quality of life (− 7.7 ± 25.36 vs – 11.31 ± 25.02, p = 0.427).

Conclusions

There is no case for advocating use of vitamin D in the management of IBS symptoms. The prevalence of vitamin D insufficiency suggests routine screening and supplementation should be implemented in this population for general health reasons.

This trial was retrospectively registered with ISRCTN (ISRCTN13277340) on 24th April 2018 after recruiting had been initiated.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02633-w.

1,25-Dihydroxyvitamin D3 and dietary vitamin D reduce inflammation in mice lacking intestinal epithelial cell Rab11a

A number of studies have examined the effects of 1,25-dihydroxyvitamin D₃ (1,25(OH)₂ D₃ ) on intestinal inflammation driven by immune cells, while little information is currently available about its impact on inflammation caused by intestinal epithelial cell (IEC) defects. Mice lacking IEC-specific Rab11a a recycling endosome small GTPase resulted in increased epithelial cell production of inflammatory cytokines, notably IL-6 and early onset of enteritis. To determine whether vitamin D supplementation may benefit hosts with epithelial cell-originated mucosal inflammation, we evaluated in vivo effects of injected 1,25(OH)₂ D₃ or dietary supplement of a high dose of vitamin D on the gut phenotypes of IEC-specific Rab11a knockout mice (Rab11a^ΔIEC ). 1,25(OH)₂ D₃ administered at 25 ng, two doses per mouse, by intraperitoneal injection, reduced inflammatory cytokine production in knockout mice compared to vehicle-injected mice. Remarkably, feeding mice with dietary vitamin D supplementation at 20,000 IU/kg spanning fetal and postnatal developmental stages led to improved bodyweights, reduced immune cell infiltration, and decreased inflammatory cytokines. We found that these vitamin D effects were accompanied by decreased NF-κB (p65) in the knockout intestinal epithelia, reduced tissue-resident macrophages, and partial restoration of epithelial morphology. Our study suggests that dietary vitamin D supplementation may prevent and limit intestinal inflammation in hosts with high susceptibility to chronic inflammation.

The Relationship between Low Serum Vitamin D Levels and Altered Intestinal Barrier Function in Patients with IBS Diarrhoea Undergoing a Long-Term Low-FODMAP Diet: Novel Observations from a Clinical Trial

Decreased serum vitamin D (VD) levels have been associated with gastrointestinal (GI) disorders, including irritable bowel syndrome (IBS). VD can also modulate the intestinal barrier. Given the link between the GI barrier’s alterations and diet, attention has aroused the positive effects of the Low FODMAP Diet (LFD) on IBS patients’ symptom profile. We evaluated the GI symptoms and the urinary and circulating markers of GI barrier function, the markers of inflammation and intestinal dysbiosis in 36 IBS patients with predominant diarrhea (IBS-D) (5 men and 31 women, 43.1 ± 1.7 years) categorized for their circulating VD levels in low (L-VD) and normal (N-VD) (cutoff = 20 ng/mL). Evaluations were performed before and after 12 weeks of LFD. At the baseline, L-VD patients showed a significantly worse symptom profile and altered small intestinal permeability (s-IP) than N-VD. After LFD, a significant increase in the circulating VD levels in both the subgroups and a significant improvement of s-IP in L-VD patients occurred. Finally, VD levels negatively correlated with the symptom score and fecal zonulin. These data highlight the close relationship between VD and the intestinal barrier and support their involvement in IBS-D pathophysiology. Moreover, the potentially positive role of LFD in the management of IBS-D was confirmed.

Treating irritable bowel syndrome through an interdisciplinary approach

Irritable bowel syndrome (IBS) is a functional disorder with a multifactorial etiology and a complex clinical picture. The recent discovery of the dysregulation of the gut-brain axis as an important pathogenetic mechanism for the development of IBS is a kind of breakthrough in the understanding of IBS and prevalent comorbidities. Nevertheless, IBS treatment still causes many problems and often turns out to be ineffective or brings only short-term effects in reducing symptom severity. In reference to the characteristics of IBS, including new findings regarding etiopathogenesis, an interdisciplinary treatment approach is proposed and the roles of medical and psychological interventions are underlined. The literature search was conducted using electronic databases with a focus on the latest publications. The review may be useful for matching the best strategy of IBS management.

Pharmacological treatments for patients with irritable bowel syndrome: An umbrella review of systematic reviews and meta-analyses

INTRODUCTION

Several pharmacological treatments are beneficial for patients with irritable bowel syndrome (IBS), and there are numbers of systematic reviews evaluating the effectiveness of these treatments. However, the overall quality of the evidence has not been quantitatively assessed. The aim of this study is to evaluate the possible biases in the published systematic reviews and determine the treatments with reliable evidence.

METHODS AND ANALYSIS

We will perform an umbrella review to identify eligible systematic reviews. A comprehensive literature search will be conducted in MEDLINE, EMBASE, and the Cochrane library for systematic reviews. We will describe the general information such as participants, interventions, outcome measurements, and conclusion. Additionally, the heterogeneity and inconsistency between trials will be assessed by the I statistical test and Cochrane Q test. We will assess risk of bias, and summarize the strength evidence.

CONCLUSION

The umbrella reviews will assess the reliability of the evidence so that doctors and patients can make better medical choices.

PROSPERO REGISTRATION NUMBER

CRD42018109597.