Relationship between circulating n-3 fatty acid concentrations and endothelial function in early adulthood.

AIMS Fish consumption is inversely associated with cardiovascular mortality, presumably because of n-3 fatty acids in fish. Whether the protection of n-3 fatty acids extends beyond clinical coronary disease to influence the early vascular biology of atherosclerosis remains unclear. This study determined whether circulating levels of n-3 fatty acids are associated with vascular endothelial function in early adulthood. METHODS AND RESULTS Three hundred and twenty-six adults (157 males, 169 females, aged 20 to 28 years) had high-resolution ultrasound measurements of flow-mediated brachial artery dilatation (FMD) (endothelium-dependent) and arterial response to glyceryl trinitrate (endothelium-independent). Levels of the n-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid in plasma and erythrocyte membranes of subjects were measured. n-3 Fatty acid levels were not related to vascular function in the whole group. In smokers, however, n-3 fatty acids were positively related to flow-mediated dilatation (plasma DHA vs. FMD: 0.045 mm. %(-1), 95% CI 0.011 to 0.079, P=0.01). Flow-mediated dilatation was also associated with n-3 fatty acid levels in subjects in the top third of the insulin, glucose and triglyceride distributions. CONCLUSION In young smokers and those with higher fasting insulin, glucose or triglyceride concentrations (factors associated with endothelial dysfunction), n-3 fatty acid levels were positively associated with flow-mediated dilatation. This raises the possibility that physiological levels of circulating n-3 fatty acids may protect the endothelium from early adulthood.