Recent developments in short-chain fatty acid metabolism.

Bacterial translocation across the bowel wall has recently been proposed as a major problem in the stressed patient. Consequently, there has been considerable interest in fostering bowel wall integrity as a barrier to bacteria and endotoxin. One postulated means to promote this barrier function has been through the provision of the preferred fuels of the bowel wall. Among these are the short-chain fatty acids (SCFAs) which are found to a limited extent in the diet but are primarily produced through the fermentation of non-digestible carbohydrates by the bacterial flora of the colon. In both animal and human studies, SCFAs have been shown to stimulate intestinal mucosal growth. Because non-digestible carbohydrates, after colonic fermentation, are precursors to SCFAs, similar effects to those found with direct provision of SCFAs may be anticipated. Pectin, beta-glucan, and lactulose are among the many available nonabsorbable carbohydrates that could serve as a source of these trophic stimulants to colonic mucosa. Short-chain fatty acids and their precursors deserve extensive and clinical evaluation to define their ultimate role in human disease.