n-3 PUFA-supplemented perioperative immunonutrition on postoperative outcomes in gastric cancer: a systematic review and meta-analysis

Objective: To evaluate the impact of perioperative immunonutritional regimens that included n-3 polyunsaturated fatty acids (n-3 PUFAs)-ranging from n-3 PUFA monotherapy to complex formulas combined with other immunonutrients-on postoperative outcomes in gastric cancer patients. Background: Although preventing postoperative complications is crucial for gastric cancer patients, consensus is lacking on the efficacy and optimal timing of administration of perioperative immunonutrition supplemented with n-3 PUFAs. Methods: We systematically searched PubMed, Embase, Web of Science, and the Cochrane Library for randomized controlled trials (RCTs) evaluating perioperative immunonutrition with n-3 PUFAs in gastric cancer surgery patients. Manual searches of reference lists were also conducted. The primary endpoint was total postoperative complications. Secondary endpoints included immune function [CD4+ T lymphocytes (CD4+ cells), CD8+ T lymphocytes (CD8+ cells), CD4+/CD8+ ratio, total lymphocytes, immunoglobulins IgA, IgG, IgM], nutritional status (transferrin, albumin, prealbumin), inflammatory markers (IL-6, TNF-α, CRP), and recovery indices (time to first flatus, length of hospital stay). Data were analyzed using RevMan v5.3 with a random-effect model. Results: Sixteen RCTs involving 1,642 patients were included. The meta-analysis demonstrated that perioperative n-3 PUFA supplementation significantly reduced the overall incidence of postoperative complications and promoted earlier recovery, as evidenced by a shortened time to first flatus and a reduced length of hospital stay. Furthermore, the n-3 PUFA group showed significant improvements in immunological (CD4+ T cell (%), CD4+/CD8+ ratio, total lymphocytes, IgA, IgG), inflammatory (IL-6, TNF-α, CRP), and nutritional (prealbumin) parameters. However, no significant differences were observed in CD8+ T cell (%), IgM, transferrin, or albumin levels between groups. Conclusion: The perioperative application of immunonutrition containing n-3 PUFAs can reduce the incidence of postoperative complications in patients with gastric cancer, improve immune function and nutritional status, mitigate inflammatory responses, and promote early postoperative recovery.