Dietary supplementation with fish oil in ulcerative colitis

Objective: To determine the efficacy of fish oil supplementation in patients with active ulcerative colitis. Design: Multicenter, randomized, double-blind, placebo-controlled, crossover trial with 4-month treatment periods (fish oil and placebo) separated by a 1-month washout. Setting: Four gastroenterology divisions. Patients: Twenty-four patients with active ulcerative colitis entered the study. Five dropped out, and one was noncompliant. Eighteen patients completed the study. All patients had active disease as manifested by diarrhea and rectal inflammation. Interventions: Treatment with prednisone and sulfasalazine was continued. Fish oil supplementation consisted of 18 Max-EPA (eicosapentaenoic acid) capsules daily (eicosapentaenoic acid, 3.24 g; and docosahexaenoic acid, 2.16 g). Placebo supplementation consisted of 18 identical capsules containing isocaloric amounts of vegetable oil. Measurements: Patients were evaluated at study entry and after each diet period. Evaluations included a review of symptoms, flexible sigmoidoscopy, rectal biopsy, and rectal dialysis to measure prostaglandin E₂ and leukotriene B₄ levels. Results: Fish oil supplementation resulted in a significant decrease in rectal dialysate levels of leukotriene B₄ from 71.0 to 27.7 pg/mL (average change, - 43.3 pg/mL; 95% CI, - 83 to - 3.6). Significant improvements were seen in acute histology index (average change, - 8.5 units from a baseline of 10.5 units; CI, - 12.9 to - 4.2) and total histology index (average change, - 8.5 units from a baseline of 14.80; CI, - 13.2 to - 3.8) as well as significant weight gain (average weight gain, 1.74 kg, CI, 0.94 to 2.54). No significant changes occurred in any variable during the placebo period. Seven patients received concurrent treatment with prednisone. During the fish oil supplementation period, the mean prednisone dose decreased from 12.9 mg/d to 6.1 mg/d and rose from 10.4 mg/d to 12.9 mg/d during the placebo diet period (P > 0.20). Conclusions: Four months of diet supplementation with fish oil in patients with inflammatory bowel disease resulted in reductions in rectal dialysate leukotriene B₄ levels, improvements in histologic findings, and weight gain.