Association between vitamin C, D, and K intake and inflammatory bowel disease risk: findings from 2009 to 2010 NHANES.

Background: Micronutrient deficiency is commonly observed in patients with inflammatory bowel disease (IBD), yet the role of certain dietary trace elements in the risk of IBD development remains unclear.

Objectives: This study aimed to investigate the relationship between vitamin C, D, and K intake and IBD risk.

Methods: This study included 3,591 participants from the 2009-2010 National Health and Nutrition Examination Survey (NHANES). Multivariable logistic regression were conducted to assess associations between vitamin C, D, and K intake and IBD risk while controlling for multiple confounders. Subgroup analyses were employed to test the robustness of the associations across participants with various characteristics. Additionally, restricted cubic spline (RCS) analysis was conducted to investigate potential nonlinear relationships.

Results: In the fully adjusted model, each 1 mcg increase in vitamin D intake was linked to an approximately 51% decrease in IBD risk (adjusted OR = 0.49, 95% CI: 0.25-0.98, p = 0.045). The benefit appeared stronger in women, individuals without hypertension, and non-smokers. No statistically significant associations were found between vitamin C or vitamin K intake and IBD risk. However, among individuals without diabetes, each 1 mcg increase in vitamin K intake was associated with an approximate 67% reduction in IBD risk (adjusted OR = 0.33, 95% CI: 0.12-0.94, p = 0.039). RCS analysis suggested a linear relationship between dietary micronutrient intake and IBD risk (vitamin D: p for nonlinearity = 0.127, p for overall = 0.015; vitamin C: p for nonlinearity = 0.984, p for overall = 0.937; vitamin K: p for nonlinearity = 0.736, p for overall = 0.434).

Conclusion: Increased vitamin D intake may reduce the risk of IBD, with more pronounced benefits in certain subgroups, highlighting the potential of vitamin D supplementation as a novel therapeutic approach for IBD prevention and management. Future well-designed studies should further test the therapeutic effects of vitamin D supplementation and investigate the associations of other dietary trace elements with IBD risk to better inform prevention and treatment approaches.