Effect of perioperative glutamine-enriched nutritional support on patients with colorectal cancer: A systematic review and meta-analysis.

BACKGROUND: Colorectal cancer (CRC) is a common malignant tumor of the digestive system that poses a serious threat to human health. During the perioperative period, patients with CRC are prone to nutritional risks and malnutrition. Compared with traditional nutritional support, immunostimulatory nutrients, including glutamine (Gln), have attracted increasing attention. Although many previous studies have reported that perioperative Gln supplementation can improve short-term clinical outcomes in patients with CRC, some studies have not demonstrated a benefit. Resolution of Gln supplementation value thus requires further exploration. AIM: To clarify the influence of perioperative Gln-enhanced nutritional support on postoperative outcomes including nutritional status, immune function, inflammation levels, morbidity due to complications, and length of hospital stay (LOS). METHODS: A comprehensive literature search was conducted (inception to June 2025). PubMed, EMBASE, Web of Science, Cochrane Library, China Biomedical Database, CNKI, VIP, and the Wanfang Electronic Database were searched. This meta-analysis ultimately included 27 studies with a total of 1643 patients; 827 patients received perioperative Gln treatment and 816 received conventional nutritional therapy. A random-effects model was used to pool relative risks (RR) and mean differences (MD) with 95% confidence intervals (CI). RESULTS: Pooled analysis showed that Gln intervention reduced morbidity associated with postoperative infectious complications (RR = 0.36; 95%CI: 0.24-0.54) and non-infectious complications (RR = 0.32; 95%CI: 0.19-0.55) and shortened the LOS by 2.31 days (MD = -2.31; 95%CI: -3.21 to -1.41) in CRC patients. Gln supplementation also increased serum albumin, prealbumin, peripheral blood lymphocyte count, and nitrogen balance levels and improved humoral and cellular immune function. We also found that postoperative tumor necrosis factor-α and C-reactive protein levels were lower in Gln-supplemented patients. By contrast, Gln supplementation did not improve CD8+ and CD4+/CD8+ levels. CONCLUSION: Gln supplementation effectively improved short-term clinical outcomes in patients with CRC.