DIETARY FISH-OIL DECREASES SUPEROXIDE GENERATION BY HUMAN NEUTROPHILS- RELATION TO CYCLOOXYGENASE PATHWAY AND LYSOSOMAL-ENZYME RELEASE

12 volunteers with slightly elevated serum triglyceride levels were gi ven 30 ml fish oil (5.4 g eicosapentaenoic acid and 3.2 g docosahexaen oic acid) daily for 4 weeks. The percentage of eicosapentaenoic acid i ncreased (P < 0.01) and the percentage of linoleic (P < 0.05) and arac hidonic acid (P < 0.01) decreased in neutrophil phospholipids. Superox ide generation by neutrophils initiated by phorbol myristate acetate d ecreased significantly from 48.6 +/- 8.8 to 34.7 +/- 11.1 nmol/10 min/ 400 000 cells (means +/- SD, P < 0.01, n = 11). Treatment of the cells with the cyclooxygenase inhibitor indomethacin had no significant inf luence on the decrease in superoxide generation, indicating that cyclo oxygenase products were not involved in this effect of fish oil. Neutr ophil elastase release did not change significantly, suggesting that n eutrophil lysosomal enzyme release and superoxide generation may be un der separate control. In conclusion, dietary fish oil decreased supero xide generation by human neutrophils without involvement of the cycloo xygenase pathway and without altering neutrophil lysosomal enzyme rele ase. Dietary fish oil could have beneficial effects in pathological co nditions with activated neutrophils, such as ischaemic heart disease.