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.