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

Abstract

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.

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

“…In a recent systematic review and meta-analysis, Chong et al [55] reported that vitamin D significantly improved IBS-SSS but found no difference between vitamin D and placebo in improving IBS-Qol, which is contradictory to our findings. On the one hand, the difference in IBS-SSS outcome can be attributed to the fact that Chong et al [55] included Tazzyman et al [56] which is a pilot study that used IBS visual analogue score (VAS-IBS) and considered underpowered to provide significant findings, hence excluded from our analysis, and Jalili et al [57] who compared soy isoflavones and/or vitamin D. However, vitamin D was administrated along with placebo to substitute soy isoflavones which can significantly impact the findings. To clarify, patients that receive a placebo have significantly improved findings compared to baseline because IBS patients' mental status is significantly affected by the placebo given their expectations and desire to receive therapy are more crucial than the drug's composition [30,58].…”

“…To clarify, they miss-extracted the data of Williams et al [31] by changing the values of IBS-Qol outcome numbers from negative to positive changing the direction of the effect of the Williams et al [31] study and their pooled analysis. We clarified the methodological flaws of Chong et al [55] in our recently published editorial [59]. In another recent review by Haung et al [60], vitamin D was effective in improving IBS-SSS which is also contradictory to our findings.…”

“…Hence, this was excluded from our analysis. On the other hand, the difference in IBS-Qol outcome can be attributed to an error in the analysis by Chong et al [55]. To clarify, they miss-extracted the data of Williams et al [31] by changing the values of IBS-Qol outcome numbers from negative to positive changing the direction of the effect of the Williams et al [31] study and their pooled analysis.…”

An Open-Label Trial Study of Quality-of-Life Assessment in Irritable Bowel Syndrome and Their Treatment

“…Many studies have been published about the beneficial effects of the Mediterranean diet as a basis for a healthy diet [36], with an important role in the management of cardiovascular diseases, obesity, or hypertension. Other studies have shown the effectiveness of the low fodmap diet [32], but, most importantly, vitamin D supplementation in the management of IBS is effective [37]. These diets have been followed in various meta-analyses, and it has been found that the diet helps reduce symptoms, and it positively influences the quality of life [38][39][40][41][42]; however, the studies have many unanswered questions, so further studies are needed.…”

Vitamin D supplementation for irritable bowel syndrome: Concerns about the meta‐analysis

“…We read with great interest the article by Chong et al 1 entitled "Vitamin D Supplementation for Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis" published in your respected journal, and we appraise the authors for conducting a high-quality systematic review. However, we detected a few significant errors in the meta-analysis that require correction to draw valid conclusions.…”