Pitfalls in short-chain fatty acid research: A methodological review.

This methodological review suggests what to do and what not to do in short-chain fatty acid (SCFA) research for researchers, supervisors, scientific reviewers, and regulatory officers. High viscosity of gut contents, existence of bacterial biofilm and of mucus layer at the mucosal surface, and rapid absorption of SCFAs make it difficult to know their concentrations at the very surface of the mucosa. As lumen or fecal concentration of SCFAs does not reflect their rate of production, these parameters should not be used as measures of SCFA production or absorption. Effects of SCFAs can vary and even become opposite at different dose, time of/after exposure or time of the day. Thus, results without dose-response, time-course, and diurnal variance experiments can be seriously misleading. It is also to note that too much emphasis on n-butyrate should be avoided.