Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic disease of the gastrointestinal (GI) tract associated with unclear etiology, leading to rectal bleeding, abdominal pain, and weight loss and repeated cycles of relapse and remission [1, 2]. CD is an IBD that can affect entire GI tract from mouth to anus and it affects mainly terminal ileum and colon. It often includes both intestinal and extra-intestinal symptoms [2, 3]. On the other hand, UC is mostly restricted to the colon and it usually involves continuous lesion in the intestinal mucosa . Most patients with IBD, especially those with CD, suffer from weight loss and malnutrition during the course of the disease [4, 5], which may be related to lack of oral intake, increased nutrient requirements, increased GI loss, and intestinal resection or bypass surgery [4, 6]. In addition, intestinal Behçet’s disease (BD), which is an intestinal invasion of BD with chronic relapsing multisystem vasculitis disorder , is similar to CD with respect to clinical courses, symptoms and treatment modalities . Therefore, there is increasing interest in patient management and nutritional status in intestinal BD as well as IBD.
Nutrients can be classified as either macronutrients or micronutrients. Macronutrients are energy-providing nutrients including carbohydrates, lipids, and proteins. Malnutrition can occur in cases of active, severe IBD, when macronutrients are not consumed or absorbed in sufficient quantities. Micronutrients, including minerals, vitamins, and trace elements, are often deficient in patients with mild disease activity or remission status [9, 10].
According to the European Society for Clinical Nutrition and Metabolism guidelines, patients with IBD should be regularly checked for micronutrient deficiencies and certain deficits should be adequately corrected . Several studies have reported vitamin and mineral deficiencies in patients with IBD; these studies assessed their symptoms and effects on the quality of life and observed widely variable clinical significance [12,13,14]. Vitamins are organic compounds and are classified as either water-soluble, including thiamine (B1), riboflavin (B2), nicotinic acid/niacin (B3), pyridoxine (B6), cobalamin (B12), biotin, pantothenic acid, folic acid, and vitamin C (ascorbic acid), or fat-soluble, including vitamins A, D, E, and K . Dietary minerals are important inorganic components that work as cofactors and catalysts in maintaining cell structure and enzymatic processes, such as calcium, phosphate, potassium, magnesium, and iron. Trace elements are necessary for the function of enzymes in the body, including zinc, copper, and selenium [9, 10].
Clinically relevant micronutrient deficiencies that occur over the course of IBD disease progression include anemia (caused by iron, folate, and vitamin B12 deficiencies), bone mineral density loss (due to insufficient calcium, vitamin D, magnesium, and vitamin K levels), impaired thrombosis (caused by folate, vitamin B6, B12 deficiency) and wound healing deficits (due to deficiencies of vitamin A, C, and zinc), and carcinogenesis (related to folate, vitamin D, and calcium deficiency) . Among them, anemia is the most common complication affecting up to 70% of patients with IBD, including UC and CD, and intestinal BD [15, 16]. Iron deficiency is the most common cause of anemia in 30–90% of patients with IBD, but folate and vitamin B12 deficiencies are also highly prevalent in these patients, especially in those with CD, compared to the general population [17,18,19]. In addition, bone density is an important factor, which affects not only the quality of life of IBD patients but also the disease course of IBD, as it is highly related to treatment modalities such as corticosteroids as well as micronutrients [20,21,22]. However, studies assessing micronutrient concentrations in patients with IBD are scarce, and there are currently no studies on micronutrients in patients with intestinal BD, to our knowledge. Therefore, we aimed to investigate the prevalence and risk factors of micronutrient deficiency in patients with IBD and intestinal BD.