Use of Beetroot Juice to Protect Against Postoperative Ileus Following Colorectal Surgery: BEET IT Study

Inclusion Criteria: * Adult patients undergoing elective colonic and upper rectum laparoscopic surgery requiring an anastomosis, without the need of conversion Exclusion Criteria: General: * \< 18 years of age * Pregnancy or breast feeding Medical: * Psychiatric pathology capable of affecting comprehension and judgment faculty * History of inflammatory bowel disease * Chronic vascular disease affecting the intestines * Chronic constipation (\<= 2 bowel movements/week) * Previous abdominal or pelvic radiation treatment * Recent (\< 3 months before inclusion) or current intra-abdominal infection or inflammation (e.g. diverticulitis, appendicitis, cholecystitis) * Use of gut motility influencing agents (e.g. tricyclic antidepressants, chronic use of laxatives) * Use of nitrates (e.g. isosorbide dinitrate, nitroglycerin), including daily consumption of beetroot juice (unless stopped for a month prior to the intervention period) * Hypotension (\< 100/60 mmHg) * Uncontrolled diabetes mellitus * Renal or hepatic insufficiency * Known allergies or intolerances to beetroot, nitrates/nitrites * Enrollment in other clinical trials/experiments, unless approved by the Ethics Committee(s) Surgical: * History of prior colorectal surgery * Emergency surgery * Open surgery * Colorectal surgery not requiring an anastomosis (e.g. colotomy, wedge resection) * More than 1 bowel anastomosis planned * Concomitant surgical procedures required (e.g. resection of liver or lung metastases) * Protective stoma planned