A randomized controlled study of evening primrose oil and fish oil in ulcerative colitis

Publisher Website
Google Scholar
Abstract
In a placebo‐controlled study, 43 patients with stable ulcerative colitis were randomized to receive either MaxEPA (n= 16), super evening primrose oil (n= 19), or olive oil as placebo (n= 8) for 6 months, in addition to their usual treatment. Treatment with MaxEPA increased red‐cell membrane concentrations of eicosapentaenoic acid (EPA) at 3 months by three‐fold and at 6 months by four‐fold (both P < 0.01), and doubled docosahexaenoic acid (DHA) levels at 6 months (P < 0.05). Treatment with super evening primrose oil increased red‐cell membrane concentrations of dihomogamma‐linolenic acid (DGLA) by 40% at 6 months (P < 0.05), whilst treatment with placebo reduced levels of DGLA and DHA at 6 months (both P < 0.05). Clinical outcome was assessed by patient diary cards, sigmoidoscopy and histology of rectal biopsy specimens. Super evening primrose oil significantly improved stool consistency compared to MaxEPA and placebo at 6 months, and this difference was maintained 3 months after treatment was discontinued (P < 0.05). There was however, no difference in stool frequency, rectal bleeding, disease relapse, sigmoidoscopic appearance or rectal histology in the three treatment groups. Despite manipulation of cell‐membrane fatty acids, fish oils do not exert a therapeutic effect in ulcerative colitis, while evening primrose oil may be of some benefit.