Micronutrients Should Be Monitored in the Real Practice for Korean Inflammatory Bowel Disease Patients

Patients with inflammatory bowel disease (IBD) are at risk for a variety of nutritional deficiencies. The reasons include that decreased nutrients intake, impaired absorption, intestinal loss, or increased metabolic requirement due to various clinical conditions such as systemic inflammation. Micronutrients are naturally occurring compounds that are not sufficiently synthesized by humans and must be obtained from the diet. Micronutrients deficiency has been reported to occur in more than half of IBD patients. Because some micronutrients are absorbed within specific locations within the gastrointestinal tract, the activity and location of a patient’s IBD determines risk for specific micronutrient deficiencies. For example, IBD at terminal ileum can cause vitamin B12 deficiency, and the disease of the proximal small intestine is likely to cause deficiencies of calcium and iron. Similarly, patients who have undergone bowel resection are also at risk for micronutrient deficiencies, and the clinical manifestation depends on the extent and location of the resected bowel. The disease activity should not be overlooked that it also contributes to micronutrient deficiency. As well as predictable reasons in an active disease such as malabsorption, diarrhea, or decreased food intake due to abdominal pain and anorexia, hypermetabolic state by systemic inflammation or drugs to treat the active diseases can impair the micronutrients absorption. For example, glucocorticoids impair Calcium, Zinc, and phosphorus absorption, causing vitamin D resistance. Long-term total parenteral nutrition can lead to deficiencies in any micronutrient not added in sufficient quantities, but most commonly include vitamins A, D, E, zinc, copper, and selenium. For above reasons, micronutrient deficiencies are more common in Crohn’s disease with small bowel disease than in ulcerative colitis, and more in active disease than at times of remission. Although the overt symptoms of micronutrient deficiency are not usually presented, micronutrient deficiency is associated with prolonged and complicated course of disease with various degrees of clinical significance. The most commonly deficient micronutrients in IBD have been known as vitamin B12, folate, iron, and vitamin D. In this article, the authors focused on the deficiencies of vitamin D, and some trace elements including zinc and selenium in IBD patients. The value of this study presented by the authors was that it was the first one to confirm micronutrients deficiencies in Asian IBD patients, compared to the previous studies only analyzing Western data. Although only several kinds of micronutrients was investigated in this study, it was an important work which should be applied to clinical practices for Asian IBD patients, who have been in a different environment from Western patients. However, some points should be reviewed analytically to evaluate their clinical relevance before the conclusions were fully accepted. First, besides showing that IBD patients have significantly lower level of vitamin D, zinc, and selenium than control, the authors suggested the risk factors for deficiencies of each micronutrient in IBD patients. However, the process seemed to be rough, and not organized due to possibilities of some confound factors. Adjustment for disease duration, activity, treatment drug, and so forth, was needed to compare Crohn’s disease and ulcerative colitis as a factor affecting each micronutrient deficiency. Although young age or female was suggested as a