Abstract
Alteration of faecal microbial flora has been suggested as a possible mechanism by which elemental diets exert their therapeutic effects in Crohn's disease. Thirteen patients with active Crohn's disease (mean CDAI 284 ± 34) were studied. Faecal samples were collected before and at weekly intervals after starting the elemental diet Vivonex for a period of 4 wk. The composition of the faecal microbial flora was assessed using a semi-quantitative method which has been calibrated against an established quantitative surface viable count technique. The only significant change in the faecal flora observed during the period of dietary treatment was a marked reduction in the scores of anaerobic lactobacilli (P ≤ 0.0001); these organisms disappeared from the stools of eight (62 per cent) patients. However, the change in lactobacilli scores was not related to changes in the clinical condition as assessed by the CDAI and established laboratory indicators of activity. The results of this study show that alteration of the faecal flora does not explain the therapeutic value of elemental diets in Crohn's disease.