Circulating Omega-3 Fatty Acids and Cardiometabolic Outcomes: A Systematic Review of Publications From UK Biobank

Studies have shown that omega-3 fatty acids may protect against cardiovascular diseases (CVDs) and related metabolic conditions. UK Biobank is a large cohort study that includes data on plasma omega-3 fatty acids at study entry and health outcomes during the follow-up period. The aim of this research is to explore the association between plasma omega-3 fatty acids (total omega-3 fatty acids, docosahexaenoic acid (DHA) and non-DHA omega-3 fatty acids) and cardiometabolic health outcomes by systematically reviewing publications from UK Biobank. Three databases (EMBASE, MEDLINE, CINAHL) were searched in September 2025 using key words. Based on inclusion/exclusion criteria, 16 publications were selected for inclusion (two cross-sectional and 14 longitudinal with a follow-up of 11 to 14 years). Sample size varied between 20,338 and 273,834 across the included studies. Eleven studies reported on CVD outcomes and five on metabolic outcomes. Plasma total omega-3 fatty acids and DHA were inversely associated with risk of coronary heart disease, CVD mortality, heart failure, haemorrhagic stroke and severe fatty liver disease. Plasma total omega-3 fatty acids were also inversely associated with risk of prediabetes and type-2 diabetes, while plasma DHA was also inversely associated with risk of coronary heart disease mortality, ischemic stroke and fatty liver disease. It is concluded that publications based on UK Biobank consistently demonstrate a significant association between higher levels of total omega-3 fatty acids or DHA in plasma and lower likelihood of poor cardiometabolic health outcomes, providing support for guidance for the population to achieve recommended intakes of these fatty acids.