Effect of regular consumption of oily fish compared with white fish on chronic plaque psoriasis

The influence of dietary advice on the severity of chronic plaque psoriasis was studied in 18 patients. Medication was standardized in all patients who were advised to eat 170 g white fish daily for a 4 week run-in period. Then the patients were randomized either to continue with the white fish diet or to substitute 170 g oily fish daily for 6 weeks. At the end of this second period the diets were reversed for a further 6 weeks. The oily fish but not the white fish diet led to a modest clinical improvement (11% and 15%, P < 0.01) which was accompanied by a rise in plasma eicosapentaenoic acid (20:5n-3) concentrations. It is concluded that dietary advice to increase the daily intake of oily fish is a useful adjunct in the treatment of psoriasis. The fish that should be recommended include mackerel, sardine, salmon, pilchard, kipper and herring.