Abstract
Meta-analyses have been conducted with conflicting results on this topic. Due to missing several eligible studies in previous meta-analysis by Lam et al., we conducted an extensive systematic review and dose-response meta-analysis of randomized controlled trials in this regard. A comprehensive search was conducted across various databases, including MEDLINE/PubMed, ISI Web of Knowledge, Scopus, and Google Scholar, until November 2023. Based on the analysis of 33 studies comprising 2,047 individuals, it was found that there was a significant increase in body weight for each 1 g/day increase in omega-3 lipids (standardized MD [SMD], 0.52 kg; 95% confidence interval [CI], 0.31, 0.73; I(2) = 95%; Grading of Recommendations Assessment, Development and Evaluation [GRADE] = low). Supplementation of omega-3 fatty acids did not yield a statistically significant impact on body mass index (BMI) (SMD, 0.12 kg/m(2); 95% CI, -0.02, 0.27; I(2) = 79%; GRADE = very low), lean body mass (LBM) (SMD, -0.02 kg; 95% CI, -0.43, 0.39; I(2) = 97%; GRADE = very low), fat mass (SMD, 0.45 kg; 95% CI, -0.25, 1.15; I(2) = 96%; GRADE = low), and body fat (SMD, 0.30%; 95% CI, -0.90, 1.51; I(2) = 96%; GRADE = very low). After excluding 2 studies, the findings were significant for BMI. Regarding the results of the dose-response analysis, body weight increased proportionally by increasing the dose of omega-3 supplementation up to 4 g/day. Omega-3 fatty acid supplementation can improve body weight, but not BMI, LBM, fat mass, or body fat in cancer patients; large-scale randomized trials needed for more reliable results. TRIAL REGISTRATION: PROSPERO Identifier: CRD42023395341.