The effect of dietary fatty acids on the gastric production of prostaglandins and aspirin-induced injury.

We have investigated in man the effect of dietary supplementation with evening primrose oil (linoleic acid 72%, gamma-linolenic acid 9%) on gastric immunoreactive PGE2 release and aspirin-induced mucosal injury. Twenty healthy volunteers received in a randomized crossover evening primrose oil (2 g b.d.) and olive oil (control) for 2 weeks each. During the last 48 hours of each period, five doses of aspirin 900 mg were taken. In gastric washings on day 7, evening primrose oil had enhanced immunoreactive PGE2 release from a mean of 38 ng/30 min (olive oil) to 80 ng/30 min (P less than 0.05). This, however, was not able to protect against aspirin-induced gastric blood loss which rose from a mean (95% confidence limits) of 1.3 (0.7-2.1) microliters 10 min-1 (evening primrose oil day 7) to 9.4 (5.4-16.5) microliters 10 min-1 (day 14). Although not effective against aspirin, similar dietary supplementation might assist in preventing peptic ulcer recurrence.