Synbiotics Improved Stool Form via Changes in the Microbiota and Short-Chain Fatty Acids in Hemodialysis Patients

Hemodialysis patients often develop constipation. We analyzed the advantage of synbiotics over prebiotics based on the stool form due to the intestinal environment in hemodialysis patients. Patients received either synbiotics or prebiotics for four weeks. The synbiotics group was treated with partially hydrolyzed guar gum containing Bifidobacterium longum BB536, while the prebiotics group was treated with the same fiber alone. The defecation status was assessed using the Bristol Stool Form Scale and abdominal bloating was evaluated using a visual analog scale. The fecal microbiota, measured by a terminal restriction fragment length polymorphism analysis, and the fecal short-chain fatty acid concentrations, measured by gas chromatography, were compared between the two groups. Synbiotics ingestion improved the individual stool form and abdominal bloating, and increased Bifidobacterium, which produces short-chain fatty acid, 13.9-fold after ingestion. In particular, acetic acid increased 2.5-fold in the synbiotics group. On the other hand, butyric acid increased 3.0-fold in the prebiotics group. Synbiotics improved the stool form in hemodialysis patients due to the composition of the intestinal microbiota and short-chain fatty acid concentrations.