Vitamin D May Improve Quality of Life in IBS but fails to Reduce Symptom Severity: Study

IBS has been described as a complex disorder characterized by dysfunction within the gastrointestinal tract. Such abnormality causes symptoms that include bloating, abdominal pain, constipation, and diarrhea. Studies in reviews clearly indicate well-established deficiency of vitamin D among patients diagnosed with IBS; as many as approximately 82% of the IBS patients present with an insufficient or deficient level of serum 25(OH)D. Systematic Review and Meta-Analysis. The researchers, Kelly C. Cara from Tufts University, aimed at finding whether the improvement of vitamin D status could help reduce the severity of IBS symptoms in those suffering from IBS by improving their quality of life.

This systematic review and meta-analysis combined data from 12 studies, including RCTs, single-arm interventions, and Mendelian randomization studies. The overall sample size of all these studies was 7,561, with the ranges of vitamin D levels at baseline ranging from deficient (<20 ng/mL) to insufficient (21–29 ng/mL). These studies went beyond a considerable geographical location, covering the countries of Iran, Egypt, Pakistan, China, UK, and US, in order to determine whether supplementation of vitamin D has any impact on IBS symptoms and quality of life for patients.

• The absolute mean difference between groups was 20.33 ng/mL higher for vitamin D than for placebo (95% CI, 12.91 to 27.74 ng/mL).

• Increases in 25(OH)D levels in participants were paralleled by improved quality of life scores among those with a baseline deficient vitamin D level, with a mean difference of 3.19 (95% CI, 2.14 to 4.24).

• Mean diffe­rence of symptom severity did not considerably reduce in RCTs; rather, it enhanced the QoL.

• It was determined that the mean difference was -55.26 (95% CI, -55.26 to 3.48).

The single-arm intervention studies, however, reported encouraging findings relating to the severity of symptoms. From a total of 97 patients in these studies, 56.7% showed complete relief, as far as IBS symptoms are concerned, including abdominal discomfort, bloating, constipation, and diarrhea, if taken vitamins D. Also, 36.1% saw significant improvement, and 6.2% improved moderately. One study reported that after 12 weeks of vitamin D supplementation, 97.5% participants replenished their vitamin D levels, and 47.5% had no IBS symptoms at follow-up.

The two Mendelian randomization studies did not find an association to result in a causal effect between serum 25(OH)D and genetic risk of IBS. One study using variance weighted by inverse method reported that vitamin D is not associated with IBS risk, using P = 0.94, MR Egger used P = 0.95, and weighted median used P = 0.76. The other reported that neither vitamin D intake nor serum 25(OH)D levels is causally associated with IBS risk (P > .05).

Vitamin D supplementation clearly improves quality of life in adults with IBS who were deficient or had insufficient levels of vitamin D. However, it is not uniformly associated with a reduction in IBS symptom severity based on available randomized controlled trials. Further studies should be conducted with greater power to establish the actual effect that vitamin D supplementation has on the management of IBS beyond correction of deficiency. The treatment in such cases remains to be multifactorial since IBS is complex.

Reference:

Cara KC, Taylor SF, Alhmly HF, Wallace TC. The effects of vitamin D intake and status on symptom severity and quality-of-life in adults with irritable bowel syndrome (IBS): a systematic review and meta-analysis. Crit Rev Food Sci Nutr. Published online September 5, 2024. doi:10.1080/10408398.2024.2400603