nutrients Review Nutritional Aspects in Inflammatory Bowel Diseases Paola Balestrieri *, Mentore Ribolsi, Michele Pier Luca Guarino, Sara Emerenziani, Annamaria Altomare and Michele Cicala Unit of Gastroenterology, Campus Bio-Medico University, 00128 Rome, Italy; [email protected] (M.R.); [email protected] (M.P.L.G.); [email protected] (S.E.); [email protected] (A.A.); [email protected] (M.C.) * Correspondence: [email protected]; Tel.: +39-06-225411; Fax: +39-06-225411638 Received: 13 January 2020; Accepted: 28 January 2020; Published: 31 January 2020 Abstract: Crohn’s disease (CD) and ulcerative colitis (UC) are chronic, relapsing, inflammatory disorders of the digestive tract that characteristically develop in adolescence and early adulthood. The reported prevalence of malnutrition in inflammatory bowel disease (IBD) patients ranges between 20% and 85%. Several factors, including reduced oral food intake, malabsorption, chronic blood and proteins loss, and intestinal bacterial overgrowth, contribute to malnutrition in IBD patients. Poor nutritional status, as well as selective malnutrition or sarcopenia, is associated with poor clinical outcomes, response to therapy and, therefore, quality of life. The nutritional assessment should include a dietetic evaluation with the assessment of daily caloric intake and energy expenditure, radiological assessment, and measurement of functional capacity. Keywords: IBD; CD; UC; malnutrition; enteral nutrition; malabsorption 1. Introduction: Crohn’s disease (CD) and ulcerative colitis (UC) are chronic, relapsing, inflammatory disorders of the digestive tract that characteristically develop in adolescence and early adulthood. The reported prevalence of malnutrition in inflammatory bowel disease (IBD) patients ranges between 20% and 85% [1,2]. Several studies have reported a prevalence of weight loss in 70%–80% of hospitalized IBD patients and in 20%–40% of outpatients with CD [3,4]. Malnutrition can occur both in UC and in CD, but the prevalence of protein–energy and specific nutrient malnutrition seems to be higher in CD compared to UC, probably because it can affect any part of the gastrointestinal tract and, mainly, the small bowel [1]. The mechanisms underlying malnutrition in inflammatory bowel disease include reduced oral food intake, malabsorption of nutrients, enteric nutrient loss, increased energy requirements due to systemic inflammation and, occasionally, iatrogenic factors (drug- and surgery-related). The assessment of the nutritional status and the need of supportive nutritional therapy play a pivotal role in the clinical care of inflammatory bowel disease patients. In this review article, we aim to focus on the role of nutrition in inflammatory bowel disease patients. 2. Mechanisms of Malnutrition in IBD Several factors contribute to malnutrition in IBD patients. It is known that a reduced oral food intake is a main determinant of malnutrition in patients with IBD. Several mechanisms are involved in the reduction of food intake. Patients with active IBD often experience loss of appetite due to nausea, vomiting, abdominal pain, and diarrhea. Medications may also induce nausea, vomiting, or anorexia [5,6]. Glucocorticoids often reduce phosphorus, zinc, and calcium absorption and may lead to osteoporosis. Long-term sulfasalazine therapy, a folic acid antagonist, might be related to Nutrients 2020, 12, 372; doi:10.3390/nu12020372 www.mdpi.com/journal/nutrients Nutrients 2020, 12, 372 2 of 11 anemia.Nutrients Hospitalization2019, 11, x FOR PEER itself REVIEW or prolonged restrictive diet may lead to a significant reduction2 of 10 food intake [7,8]. HospitalizationMalabsorption itself is, or among prolonged other restrictive factors, strongly diet may related lead to to a mucosalsignificant alterations, reduction suchof food as intake impaired epithelial[7,8]. transport and loss of epithelial integrity. It has been reported that ileal involvement in CD Malabsorption is, among other factors, strongly related to mucosal alterations, such as impaired patients plays a relevant role in reducing nutrients absorption [9]. In particular, alterations of ionic epithelial transport and loss of epithelial integrity. It has been reported that ileal involvement in CD transport cause the loss of electrolytes and fluids. Moreover, active inflammation leads to a chronic patients plays a relevant role in reducing nutrients absorption [9]. In particular, alterations of ionic loss of blood and proteins within the intestinal lumen. transport cause the loss of electrolytes and fluids. Moreover, active inflammation leads to a chronic Small intestinal bacterial overgrowth is a hallmark of IBD patients and is related, among loss of blood and proteins within the intestinal lumen. severalSmall factors, intestinal to chronic bacterial intestinal overgrowth inflammation is a hallmark or surgicalof IBD patients removal and of is the related, ileocecal among valve. several Small intestinalfactors, to bacterial chronic intestinal overgrowth inflammation may contribute or surgical to increased removal of intestinal the ileocecal permeability valve. Small [10 intestinal–15]. It has beenbacterial demonstrated overgrowth that may bacterial contribute overgrowth to increased and increasedintestinal intestinalpermeability motility [10–15]. play It ahas key been role in energydemonstrated intake [ 16that,17 bacterial]. In particular, overgrowth a small and intestinal increased bacterial intestinal overgrowth motility play reduces a key therole digestion in energy and absorptionintake [16,17]. of nutrients In particular, in addition a small to intestinal producing bacterial osmotically overgrowth active metabolitesreduces the thatdigestion contribute and to discomfortabsorption and of nutrients diarrhea. in The addition consequent to producing accelerated osmotically gastrointestinal active metabolites transit reduces that contribute the contact to time ofdiscomfort the luminal and contents diarrhea. with The the consequent mucosal accelerated surface and, gastrointestinal therefore, leads transit to malabsorption. reduces the contact time of theSurgery luminal plays contents a pivotal with rolethe mucosal in determining surface nutrientsand, therefore, malabsorption leads to malabsorption. by inducing diarrhea across severalSurgery mechanisms. plays a pivotal The resection role in determining of large small-bowel nutrients malabsorption segments is by usually inducing followed diarrhea by across reduced digestionseveral mechanisms. and absorption The resection of nutrients of large and, small therefore,‐bowel by segments watery is diarrhea. usually followed Moreover, by areduced large ileal resectiondigestion leads and to absorption reduced intestinal of nutrients uptake and, of therefore, bile acids by and, watery therefore, diarrhea. causes Moreover, bile salt diarrhea a large ileal [18– 21]. Itresection has been leads proved to reduced that a surgical intestinal resection uptake of of the bile ileum acids of and, more therefore, than 100 causes cm leads bile tosalt a diarrhea loss of bile [18– acids which21]. It exceeds has been the proved rate ofthat hepatic a surgical synthesis resection [22 ].of As the a ileum consequence of more than of the 100 depletion cm leads of to the a loss bile of acid pool,bile fatacids digestion which exceeds and absorption the rate of is hepatic impaired, synthesis thus determining [22]. As a consequence steatorrhea of [23 the]. depletion of the bileChronic acid pool, bowel fat digestion inflammation and absorption or intestinal is impaired, surgery thus may determining accelerate the steatorrhea intestinal [23]. transit. A rapid Chronic bowel inflammation or intestinal surgery may accelerate the intestinal transit. A rapid gastrointestinal transit may limit the contact time of the luminal contents with the mucosal surface, gastrointestinal transit may limit the contact time of the luminal contents with the mucosal surface, thus leading to malabsorption and resulting in greater stool volume and diarrhea. Mechanisms of thus leading to malabsorption and resulting in greater stool volume and diarrhea. Mechanisms of malnutrition in IBD patients are depicted in Figure1. malnutrition in IBD patients are depicted in Figure 1. FigureFigure 1. 1. MechanismsMechanisms of of malnutrition malnutrition in in inflammatory inflammatory bowel bowel disease disease (IBD) (IBD) patients. patients. 3.3. Clinical Clinical Aspects Aspects ofof MalnutritionMalnutrition in in Patients Patients with with IBD IBD MalnutritionMalnutrition is is a a common common condition condition among among IBD IBD patients patients and and can can be be recognized recognized by protein–energyby protein– malnutrition,energy malnutrition, an altered an altered body composition,body composition, and and micronutrient micronutrient deficiencies. deficiencies. During During thethe course course of theof disease,the disease, protein–energy protein–energy malnutrition malnutrition and and deficiencies deficiencies of specific of specific nutrients nutrients may may represent represent clinical concernsclinical concerns in IBD patients, in IBD patients, and their and prevention their prevention is essential is essential to avoid to avoid complications. complications. MalnutritionMalnutrition is is one one of of the the most most important important factors factors associated associated with with a poor a poor clinical clinical outcome outcome in patients in withpatients IBD [with24,25 IBD]. The [24,25].