Marine-Based Omega-3 Fatty Acids and Metabolic Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

backgroundMetabolic syndrome (MetS) is a set of cardiometabolic abnormalities, including central obesity, dyslipidemia, hypertension, and hyperglycemia, that substantially increases the risk of cardiovascular disease and type 2 diabetes. Marine-derived omega-3 polyunsaturated fatty acids (

methodsFollowing PRISMA guidelines, PubMed, Embase, Scopus, and Web of Science were searched to June 2024 for RCTs in adults with MetS or its components. Eligible trials assessed marine-derived omega-3 supplementation (EPA/DHA) versus placebo or control and reported at least one MetS diagnostic criterion (triglycerides, HDL cholesterol, fasting plasma glucose, blood pressure, or waist circumference) or related parameter (LDL cholesterol, HOMA-IR, or HbA1c). Data were extracted in duplicate and quality assessed using the Cochrane Risk-of-Bias Tool. Trials were categorized by dose-low (<1000 mg/day), medium (1000-2000 mg/day), and high (>2000 mg/day)-and duration: short-term (ST; ≤8 weeks), medium-term (MT; >8-12 weeks), and long-term (LT; >12 weeks). Meta-regression using ordinary least squares estimated dose-duration effects. Publication bias was assessed with funnel plots and Egger's test for outcomes with ≥3 studies.

resultsTwenty-one RCTs (

conclusionsMarine-derived omega-3 supplementation produces substantial triglyceride reductions, especially at doses >2000 mg/day for ≥8 weeks. HDL cholesterol and blood pressure benefits are not consistent, fasting glycemia is largely unaffected, and LDL cholesterol may increase, especially in low doses. High-dose marine omega-3s can be considered as part of dietary strategies for MetS management, with monitoring for LDL changes. Standardized intervention protocols and long-term RCTs are needed to clarify dose and duration-response relationships.