Implications of dietary modulation of the arachidonic acid metabolism in psoriasis by means of fish oil rich in eicosapentaenoic acid

We studied the metabolism of endogenous arachidonic acid in polymorphonuclear leukocytes and platelets from blood samples obtained at the start and end of the treatment period during a randomized, double blind, 11-week study comparing the effect of daily administration of fish oil rich in eicosapentanoic acid (2,59 g/day) and olive oil in 18 patients with chronic stable plaque psoriasis. After 8 weeks of treatment, we found a statistically significative decrease in 12-L-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and 12(S)-hydroxy-6,8,10,14-eicosatetraenoic acid (12-HETE) production following 5 minutes' incubation of platelets from patients being treated with fish oil and a significative increase in HHT and 12-HETE production in platelets from patients receiving olive oil capsules, with respect to the values obtained at the beginning of the treatment period.