Blood omega-3 fatty acids and coronary artery stenosis: a postmortem study

The role of omega-3 fatty acids in the atherosclerotic process remains unclear. Early studies demonstrated a profound anti-atherogenic effect of cod liver oil in a pig model, and autopsy reports from Alaska Natives consuming omega-3 rich diets have supported this hypothesis, but meta-analyses of omega-3 randomized trials have produced mixed results vis-à-vis cardiovascular disease. The present study was undertaken to examine the relationship between post-mortem blood omega-3 levels and maximal stenosis of the coronary arteries at autopsy. Blood was collected from the femoral artery of 112 sequential fatalities and analyzed for fatty acid composition. The erythrocyte EPA + DHA level (the omega-3 index) was found to have degraded compared to levels in 30 living controls, but the ratio of Arachidonic Acid (AA) to EPA was unaffected, thus it was used as a biomarker of omega-3 status. We found no association between the maximal coronary artery stenosis and the AA: EPA ratio. The omega-3 index estimated from the AA: EPA ratio in the cases was 2.1%, one of the lowest mean values for any population yet tested. Thus, the lack of association between omega-3 status and coronary atherosclerosis may be due to the very low omega-3 index in this cohort.