Do antioxidants and polyunsaturated fatty acids have a combined association with coronary atherosclerosis?

To evaluate the antioxidant hypothesis with regard to atherosclerosis, we compared plasma selenium, serum alpha-tocopherol, serum polyunsaturated fatty acids (PUFA), and the ratios of selenium and alpha-tocopherol to PUFAs in subjects with varying degrees of coronary atherosclerosis. Cases had more than 85% stenosis in at least one coronary vessel and controls had less than 50% stenosis in all three vessels. Plasma selenium was significantly lower in cases than controls (95.1 +/- 21.0 micrograms/l and 108.8 +/- 29.3 micrograms/l, respectively). Though alpha-tocopherol and PUFA levels were similar in both groups, the ratios Se/linoleic acid, Se/total PUFA and Se/total n-6 acids were significantly lower in cases. In particular, these differences were observed in subjects with low serum alpha-tocopherol level (below the median; 1452 micrograms/dl). Moreover, in this subgroup the ratio Se/PUFA was significantly lower in cases than in controls for all PUFAs except eicosapentaenoic and docosahexaenoic acid. Though definitive conclusions cannot be drawn from our data, it is hypothesized that high PUFA levels, when insufficiently protected by antioxidants against peroxidation, may indicate a higher risk of atherosclerosis.