How should vitamin deficiencies be managed in patients with Crohn's disease?

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Last updated: June 16, 2025View editorial policy

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From the Guidelines

Vitamin deficiencies in Crohn's disease patients should be managed through a combination of targeted supplementation, dietary adjustments, and regular monitoring, prioritizing vitamin B12, vitamin D, iron, folate, calcium, and magnesium supplementation to prevent complications and improve quality of life. The management of vitamin deficiencies in Crohn's disease is crucial to prevent morbidity, mortality, and improve quality of life. According to the most recent and highest quality study 1, patients with Crohn's disease are at risk of vitamin B12 deficiency, particularly those with ileal involvement or resection of more than 30 cm of the distal ileum.

  • Vitamin B12 supplementation is recommended as monthly intramuscular injections of 1,000 mcg for those with terminal ileum disease or resection, or as daily oral doses of 1,000-2,000 mcg.
  • Vitamin D supplementation is also essential, with a recommended dose of 1,000-2,000 IU daily, and higher doses (up to 50,000 IU weekly) for those with severe deficiency until levels normalize 1.
  • Iron deficiency should be addressed with oral ferrous sulfate 325 mg 1-3 times daily between meals, or with intravenous iron (such as iron sucrose or ferric carboxymaltose) for those with severe anemia or intolerance to oral preparations.
  • Folate supplementation of 1 mg daily is recommended, especially for patients on methotrexate.
  • Calcium (1,000-1,500 mg daily) and magnesium (250-400 mg daily) are also important, particularly for patients on corticosteroids or with malabsorption. Regular blood monitoring every 3-6 months is essential to adjust supplementation as needed and prevent complications like osteoporosis, anemia, and neuropathy 1. The co-management with a registered dietitian is also recommended, especially for patients with malnutrition, small bowel syndrome, enterocutaneous fistula, and/or those requiring more complex nutrition therapies 1. It is also important to note that malnutrition is common in patients with Crohn's disease, and a detailed nutritional history and nutrition-focused physical examination should be performed to identify malnutrition 1. In summary, a comprehensive approach to managing vitamin deficiencies in Crohn's disease patients is necessary to improve outcomes and quality of life.

From the Research

Vitamin Deficiencies in Crohn's Disease

Vitamin deficiencies are a common issue in patients with Crohn's disease, with various studies highlighting the prevalence of deficiencies in vitamins such as B12, folate, and vitamin D.

  • The prevalence of vitamin B12 deficiency in Crohn's disease patients was found to be 15.6% in one study 2, while another study reported a prevalence of 33% 3.
  • Folate deficiency was also found to be common, with a prevalence of 22.2% in one study 2.
  • Vitamin D deficiency is also common among patients with Crohn's disease, with several factors contributing to this deficiency, including inadequate exposure to sunlight and impaired conversion of vitamin D to its active metabolite 4.

Risk Factors for Vitamin Deficiencies

Several risk factors have been identified for vitamin deficiencies in Crohn's disease patients, including:

  • Ileal resection, which was found to be a risk factor for vitamin B12 deficiency 2, 3
  • Disease activity, which was found to be a risk factor for folate deficiency 2
  • Terminal ileal inflammation, which was found to be a risk factor for vitamin B12 deficiency 3
  • Disease duration and age at onset, which were found to be associated with vitamin B12 and folate levels 5

Management of Vitamin Deficiencies

Regular screening for vitamin deficiencies is recommended for patients with Crohn's disease, particularly those with risk factors such as ileal resection or active disease 2, 3.

  • Patients with Crohn's disease should be regularly followed-up for vitamin B12 and folate levels to supplement them where needed 5.
  • Optimal vitamin D levels are also important, with emerging evidence suggesting that 25(OH)D concentrations of ≥75 nmol/l may be required for non-skeletal effects 4.

References

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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