Effects of enteral immunonutrition enriched with multiple immunonutrients on clinical outcomes of patients who underwent gastric cancer surgery: a systematic review and meta-analysis

Objective: To evaluate the clinical efficacy of enteral immunonutrition (EIN) compared to standard enteral nutrition (EN) in patients undergoing gastric cancer surgery. Methods: We searched major databases for randomized controlled trials (RCTs) published up to December 2025. Nineteen RCTs involving 1,653 patients were included. Outcomes assessed included infectious and total complications, length of hospital stay (LOS), gastrointestinal tolerance, and immune-inflammatory markers. Results: Compared to EN, EIN significantly reduced the incidence of infectious complications (OR = 0.48), gastrointestinal intolerance, and total complications. It also shortened LOS (MD = -1.24 days) and time to first flatus. EIN improved immune parameters (increased IgG, IgM, IgA, transferrin) and reduced inflammatory markers (WBC, CRP). Subgroup analysis indicated that perioperative administration yielded the most significant benefits, while preoperative-only intervention lacked sufficient evidence. Intervention durations > 7 days showed superior outcomes, with regimens within 10 days offering an optimal balance of efficacy and feasibility. Conclusion: Perioperative enteral immunonutrition, particularly when administered for 7-10 days, is associated with reduced postoperative complications, improved humoral immunity, and shorter hospital stay in patients undergoing gastric cancer surgery. Given the moderate certainty of evidence for primary outcomes, the low certainty for several secondary outcomes, and the evidence of small-study effects for total complications, EIN may be considered as a component of perioperative nutritional support- particularly in patients with established nutritional risk-while routine use should be guided by individualized assessment and confirmed by larger high-quality multicenter trials.