Br J Rheumatol. 1997 Jan; 36(1): 64-8.

Faecal microbial flora and disease activity in rheumatoid arthritis during a vegan diet.

Peltonen R, Nenonen M, Helve T, Hänninen O, Toivanen P, Eerola E.

Department of Medicine, Turku University Central Hospital, Finland.

To clarify the role of the faecal flora in the diet-induced decrease of rheumatoid arthritis (RA) activity, 43 RA patients were randomized into two groups: the test group to receive living food, a form of uncooked vegan diet rich in lactobacilli, and the control group to continue their ordinary omnivorous diets. Based on clinical assessments before, during and after the intervention period, a disease improvement index was constructed for each patient. According to the index, patients were assigned either to a group with a high improvement index (HI) or to a group with a low improvement index (LO). Stool samples collected from each patient before the intervention and at 1 month were analysed by direct stool sample gas-liquid chromatography of bacterial cellular fatty acids. This method has proved to be a simple and sensitive way to detect changes and differences in the faecal microbial flora between individual stool samples or groups of them. A significant, diet-induced change in the faecal flora (P = 0.001) was observed in the test group, but not in the control group. Further, in the test group, a significant (P = 0.001) difference was detected between the HI and LO categories at 1 month, but not in the pre-test samples. We conclude that a vegan diet changes the faecal microbial flora in RA patients, and changes in the faecal flora are associated with improvement in RA activity.