Vitamin D improves inflammatory bowel disease outcomes: Basic science and clinical review

Table 1 Vitamin D supplementation improves disease activity and outcomes in human inflammatory bowel disease

Ref.	n	Methodology	Aims	Intervention	Definition of improvement	Conclusions
Miheller et al[76]	37	Prospective single cohort study	Compare the effects of active vitamin D and plain vitamin D on bone health and disease status in Crohn’s disease patients	Group A: 2 μg × 0.25 μg alfacalcidiol (active vitamin D) daily Group B: 1000 IU cholecalciferol daily (plain vitamin D)	Assessment: Osteocalcin (OC) and beta-CrossLaps (βCL) concentrations	Significant reduction in βCL and OC concentrations showed decelerated bone resorption and bone turnover in the active vitamin D group compared to the plain vitamin D group at 6 wk and 3 mo (P < 0.05) Significant reduction in disease activity and improved quality of life in the active vitamin D group at 6 wk (P < 0.05) No difference at 12 mo
					CDAI, CRP, IBD-questionnaire (IBD-Q)
					Improvement: Significant decrease in OC and βCL concentrations
					Significant decrease in CDAI and IBDQ scores and CRP concentrations
Jørgensen et al[74]	94	A multi-centre randomized double blinded placebo controlled trial	Assess the efficacy of vitamin D supplementation in reducing the risk of relapse in Crohn’s disease patients compared to placebo	Treatment group: 1200 IU vitamin D3 + 1200 mg calcium/d Placebo group: placebo + 1200 mg calcium/d	Assessment: CDAI Improvement: Decreased proportion of patients who achieve a CDAI score of 150+ and a 70 point increase in CDAI compared to baseline	Decreased risk of relapse (29% to 13%) at 1 yr with vitamin D treatment, but did not reach significance (P = 0.06)
Ananthakrishnan et al[72]	3217	Retrospective study	Assess the association between plasma 25(OH)D3 levels and IBD related surgeries and hospitalizations Assess changes in these outcomes after normalization of IBD patients’ vitamin D levels	None	Assessment: Risk of IBD-related surgery or hospitalization (OR); Improvement: Reduction in risk (OR < 1) for surgery or hospitalization	Low levels of vitamin D significantly increased risk for IBD-related surgery and hospital admissions
						(OR = 2.05; 95%CI: 1.53-2.75 for Crohn’s disease and OR = 1.75; 95%CI: 1.21-2.52 for ulcerative colitis)
						Achieving normal vitamin D levels decreased risk of Crohn’s disease-related surgery
						(OR = 0.56; 95%CI: 0.32-0.98)
Yang et al[77]	18	Prospective clinical pilot study	Establish the oral dose of vitamin D3 required to achieve serum 25(OH)D3 concentrations above 40 ng/mL (100 nmol/L) in mild-moderate Crohn’s disease patients Assess improvement in disease activity and quality of life after vitamin D supplementation in Crohn’s disease patients	Initiated on 1000 IU per day of vitamin D3 for 2 wk. Increased dose every two wk by 1000 IU/d until achievement of serum 25(OH)D level of 40 ng/mL occurred or patients were taking a total of 5000 IU/d	Assessment: Dose of vitamin D3 and serum 25(OH)D3 levels CDAI and IBDQ Improvement: Increase in serum 25(OH)D3 levels Reduction in CDAI scores of > 70 points or achievement of CDAI score < 150, and increase in IBDQ scores	Vitamin D supplementation improved vitamin D status at 24 wk (P < 0.001). 78% of patients required 5000 IU/d of vitamin D3, suggesting this is an effective dose in raising serum 25(OH)D3 levels in mild-moderate Crohn’s patients
						Vitamin D treatment significantly improved disease activity and quality of life at 24 wk (P < 0.001)

CDAI: Crohn’s disease activity index; CRP: C-reactive protein; IBD: Inflammatory bowel disease.