Frequently Asked Questions

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Vitamin D

Patients with Inflammatory Bowel Disease (IBD) have an increased incidence of Vitamin D deficiency. (1,2) Vitamin D receptor deficiency and vitamin D ligand deficiency both result in more severe experimental IBD.


In inflammatory disease of the intestines, rapid movement of materials through the digestive system can reduce overall calcium absorption. Calcium absorption from the intestine is also a vitamin D-dependent process; the lower the body vitamin D levels, the less calcium that is absorbed. Calcium deficiency has been reported in 13% of patients with IBD.(3) Separately patients with IBD have been found to have deceased calcium intake in 23% to 80% of IBD patients.(4)


Anemia is the most common systemic complication of IBD.(5) Almost every anemic patient with IBD demonstrates some degree of iron deficiency.(6) One study noted that 30% of patients with IBD have iron deficiency anemia.(7) Between 36% and 90% of adults with IBD ultimately develop iron deficiency.(8)

Vitamin B12 and Folate

Vitamin B12 (cobalamin) and folic acid (folate) are vitamins and coenzymes involved in a series of complex biochemical reactions, including DNA synthesis. Vitamin B12 deficiency can result in anemia; it has been reported in approximately 20% of both adult and pediatric IBD patients.(9) Folate deficiency can cause and worsen anemia in IBD patients.(10). Folic acid is an essential co-factor in the metabolic route of homocysteine-methionine. Folate deficiency may result in hyperhomocysteinemia resulting in an increased incidence of thromboembolic events.

Selenium, Zinc and Magnesium

Selenium deficiency has been noted in patients with even mild IBD.(11) Low levels of serum selenium have been seen in children with IBD as compared to controls.(12) Magnesium deficiency has been reported in 13-88% of patients with IBD.(13) Magnesium losses are accelerated with increased diarrheal output.(14) Low magnesium levels in IBD patients have been reported to cause fatigue, tetany, heart arrhythmias and altered gastrointestinal motility.(15,16) Besides reduced ingestion of nutrients in IBD and poor absorption through inflamed mucosal membranes, intraluminal factors may play an additional role in the decreased absorption of some nutrients. Magnesium, selenium and zinc can form soap complex in the small intestine due to their mixing and reaction with poorly absorbed fats.(17)


IBD is a challenging disease with over 1 million people in the United States with the diagnosis, over 30,000 new cases annually, and over 2 million ambulatory care visits yearly. (18) There is compelling data within the literature pointing to micronutrient deficiencies in the setting of IBD. Although any vitamin or mineral may become deficient in IBD patients, Vitamin D, calcium, iron, vitamin B12, folate, zinc, selenium and magnesium are the most common and may have significant clinical consequences.


1.) Siffledeen JS, Siminoski K, Steinhart H, et al. The frequency of vitamin D deficiency in adults with Crohn’s disease. Can J Gastroenterol. 2003;17:473-478.
2.) Tajika M, Matsuura A, Nakamura T, et al. Risk factors for vitamin D deficiency in patients with Crohn’s disease. J Gastroenterol.2004;39:527-533.
3.) Massironi S, Rossi RE, Cavalcoli FA, et al. Nutritional deficiencies in inflammatory bowel disease: therapeutic approaches. Clin Nutr 2013;32:904-910
4.) Vagianoski K, Bector S, McConnel J, et al. Nutrition assessment of patients with inflammatory bowel disease. J Parent Ent Nutr 2007;31:185-191
5.) Schreiber S, Wedel S. Diagnosis and treatment of anemia in inflammatory bowel disease. Inflamm Bowel Dis 1997;3:204 –216
6.) Horina JH, Petritsch W, Schmid CR, et al. Treatment of anemia in inflammatory bowel disease with recombinant human erythropoietin: results in three patients. Gastroenterology 1993;104:1828 –1831
7.) Thomson ABR, Brust R, Ali MAM, et al. Iron deficiency anemia in inflammatory bowel disease, Am J Dig Dis 1978;23:705-709
8.) Gomollón F, Gisbert JP. Anemia and inflammatory bowel diseases. World J Gastroenterol 2009;15:4659-4665.
9.) Yakut M, Ustün Y, Kabaçam G, et al. Serum vitamin B12 and folate status in patients with inflammatory bowel diseases. Eur J Intern Med 2010;21:320-323
10.) Goh J, O’Morain A. Review article: nutrition and adult inflammatory bowel disease. Aliment Pharmacol Ther 2003;7:307-320
11.) Hinks LJ, Inwards KD, Lloyd B, et al. Reduced concentrations of selenium in mild Crohn’s disease. J Clin Pathol1988;41:198-201
12.) Ojuawo A, Keith l. Serum concentrations of zinc, copper and selenium in children with inflammatory bowel disease. Centr Afr J Med 2002;48:116-119
13.)Galland L. Magnesium and inflammatory bowel disease. Magnesium 1988;7:78-83
14.) Nylin H, Dyckner T, Ek B, et al. Magnesium in Crohn’s disease. Acta Med Scan Suppl 1982;661:21-25.
15.) Hessov I, Hasselblad C, Fasth S, et al. Magnesium deficiency after ileal resection for Crohn’s disease. Scan J Gastroenterol 1983;18:643-649
16.) Galland L. Magnesium and inflammatory bowel disease. Magnesium 1988;7:78-83
17.) Andersson H, Bosaeus I, Brummer R-J, et al. Nutritional and metabolic consequences of extensive bowel resection. Dig Dis 1986;4:193–202
18.) Weisshof R, Chermesh I. Micronutrient deficiencies in inflammatory bowel disease. Curr Opin Clin Nutr Metab Care. 20;18:576–581