Perioperative Nutritional Optimization in Inflammatory Bowel Diseases: When and How?

Abstract Inflammatory bowel diseases (IBDs), including ulcerative colitis (UC) and Crohn's disease (CD), are commonly associated with important changes in nutritional status (NS). Both malnutrition and obesity have a negative impact on the course of both diseases, with greater risks of postoperative complications, such as anastomotic dehiscences, reoperations, prolonged hospitalizations, and increased mortality. The diagnostic criteria for identifying individuals at nutritional risk, with clear indication for preoperative nutritional therapy, involves several factors. Oral nutrition should be the first choice of nutritional support. If the patient has difficulty in consuming food, the enteral route is the second option, through elementary (amino acids), semi-elementary (oligopeptides), or polymeric (whole proteins) formulas. When oral or enteral routes are not indicated (in the presence of intestinal obstruction or ischemia, fistula, or bleeding), total parenteral nutrition can meet the daily nutritional needs of the critically ill patient. Nutritional support can be performed exclusively or in an associated way, which will depend on the nutritional severity of the patient with IBD. Nutritional screening should be performed at all stages of the disease, always individually and with professionals with experience in IBD. The reduction of complications in the perioperative period is not only associated with adequate surgical technique, but also with adequate nutritional support and clinical preparation before surgery. Therefore, the dietitian with a focus in IBD has an important role in the multidisciplinary team, collaborating with all stages of treatment and with the optimization of the nutritional status of the surgical patient.