Effects of omega-3 supplementation on gastrointestinal cancers and treatment-related complications: an umbrella review of meta-analyses

Abstract

Background Many meta-analyses and systematic reviews have explored the impact of omega-3 supplementation on clinical outcomes in individuals with gastrointestinal (GI) cancers. Thus, this study aimed to capture the effects of omega-3 supplementation on GI cancers and associated complications.Methods This umbrella study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive advanced search was executed across Scopus, PubMed, and Web of Science until 25 January 2025. Data were pooled by using random-effects models based on heterogeneity. The entire statistical analysis was performed via RStudio and R. The statistical analysis results are presented as the mean difference (MD), standard mean difference (SMD), and relative risk (RR) in conjunction with their 95% confidence intervals (CIs).Results Eight meta-analysis papers were included in our umbrella review. Omega-3 fatty acid supplementation improved the serum concentrations of tumor necrosis factor alpha (TNF-alpha) (SMD: -0.34; 95% CI: -0.56, -0.11), interleukin-6 (IL-6) (SMD: -0.30; 95% CI: -0.49, -0.12; MD: -4.96; 95% CI: -6.62, -3.30), and C-reactive protein (CRP) (MD: -5.46; 95% CI: -10.06, -0.87). Omega-3 supplementation improved the CD4+/CD8+ ratio (SMD: 0.48; 95% CI: 0.26, 0.71) and reduced the length of hospitalization (MD: -2.45 d; 95% CI: -3.11, -1.80). Omega-3 supplementation was associated with a 24% significant reduction in the risk of overall complications (RR: 0.76; 95% CI: 0.67, 0.86).Conclusion Omega-3 supplementation may reduce the risk of overall complications and length of hospitalization in individuals suffering from GI cancers. Additionally, supplementation with omega-3 may alleviate the levels of pro-inflammatory cytokines such as TNF-alpha and IL-6, and acute-phase proteins such as CRP.