Perioperative nutrition therapy to optimize colorectal patient outcomes: A systematic review and meta-analysis

Background: Malnutrition is an independent risk factor for postoperative complications—particularly surgical site infections—and recovery delays following colorectal surgery. While some evidence suggests perioperative nutritional interventions have the potential to decrease complication rates, this literature is heterogeneous with difficult to control implementation barriers. We conducted a systematic review and meta-analysis to appraise available evidence regarding perioperative nutritional interventions. Methods: We searched Medline, Embase, CAB Abstracts, and CINAHL between 2000 and 2023 for studies assessing perioperative protein supplementation, immunonutrition, carbohydrate loading, and postoperative diet progression in colorectal surgery patients. Individual study risk of bias and overall strength of evidence (SOE) were evaluated using standardized methods. We used random-effects modeling for meta-analyses of study-level data when ≥3 studies were available. Results: Twenty-seven eligible studies underwent data extraction. Ten were low/moderate risk of bias. Compared to dietary advice alone, protein supplementation and immunonutrition may show a benefit in lower surgical site infection rates, and carbohydrate loading may result in no difference (all low SOE). Both immunonutrition and carbohydrate loading probably do not impact anastomotic leak rates (moderate SOE). Immunonutrition and carbohydrate loading may result in no length of stay differences (low SOE). Evidence was insufficient assessing the optimal diet immediately following surgery. Conclusions: Perioperative colorectal surgery nutrition interventions are heterogeneous with current evidence suggesting small to negligible benefits regarding postoperative complications. No studies comparing low-fiber diet to regular diet met inclusion criteria. The majority of evidence is insufficient, highlighting research opportunities to further enhance nutritional optimization and limit complications.