Dietary fatty acids, membrane transport, and oxidative sensitivity in human erythrocytes.

This study examined effects of dietary n-3 fatty acids on age-related changes in erythrocyte anion transport and susceptibility to oxidation. Blood was drawn from healthy adult volunteers before and after six weeks' supplementation (nine/group) with 4.0 g/day of safflower oil (containing 2.9 g n-6 fatty acids) or fish oil (containing 1.2 g long-chain n-3 fatty acids). Following density separation of young and old erythrocytes, membrane anion transport and cell membrane lipid composition were measured. Oxidative damage was measured in erythrocyte ghosts exposed to a free radical generator. Fish oil significantly increased 16:0 and 20:5n-3 in ghosts of both young and old cells, and 22:5n-3 and 22:6n-3 in old cells alone. Safflower oil increased 16:0, 18:0, 18:1n-9, and 22:5n-6 in ghosts of young cells only. The age-dependent increase in membrane anion transport (P < 0.01) was decreased by dietary fish oil supplementation, but not by safflower oil supplementation. Safflower oil and fish oil increased the susceptibility of both young and old erythrocytes to oxidative damage by free radical generation (P < 0.001).