(Gut 1999;44:483-489)

SUMMARY 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.

Urinary excretion of orally administered lactulose and 51 chromium labelled ethylenediamine tetra-acetate (5lCr-EDTA) was measured in 12 healthy adult subjects and in six patients with ileostomies to assess intestinal permeability. In normal subjects, 24 hour urinary recovery of 51Cr-EDTA was significantly greater than that of lactulose (mean (SEM) 2*27 (0-15) v 0*50 (0.08)% oral dose; p<0001), but in ileostomy patients recovery of the two markers was the same. In normal subjects, therefore, the difference between the two markers may arise from bacterial breakdown of lactulose but not of 51Cr-EDTA in the distal bowel, urinary excretion of lactulose representing small intestinal permeation and that of 51Cr-EDTA representing both small and large intestinal permeation. The markers were then given simultaneously to nine patients receiving non-steroidal antiinflammatory drugs (NSAIDs) for rheumatoid arthritis and osteoarthritis. The 24 hour urinary recovery of 5ICr-EDTA in the patients was significantly greater than normal (4-64 (1-20) v 2-27 (0.15)% oral dose; p<0-01), but that of lactulose was not significantly affected. Moreover, the increase in 51Cr-EDTA recovery was most noticeable in the later urine collections. Both of these findings suggest that NSAIDs may increase colonic permeability.