Impact of dietary fiber‐based SCFA mixtures on colon epithelial barrier function (822.1)

Abstract

Patients with HIV, obesity, and inflammatory bowel disease often have impaired gut barrier function. Short chain fatty acids (SCFAs), particularly butyrate, provide energy to the intestinal epithelium and improve barrier function. Our lab reported various fibers have different fermentation profiles, generating SCFAs varying in total concentrations and proportions of acetate, propionate, and butyrate. To study the impact of SCFA profiles of various fibers on gut barrier function, SCFA mixtures with 5, 20, and 50% butyrate proportion were designed to correspond to SCFA profiles of tested fiber fermentations, and were subjected to healthy and LPS/TNF‐α treated Caco‐2 cell monolayers. Integrity of monolayers was indicated by transepithelial electric resistance, dextran flux, and tight junction (TJ)‐related protein levels. Pro‐inflammatory genes were determined by qPCR. Total concentration of 40‐60 mM SCFA with 20% butyrate improved barrier function without causing damage to the monolayer. Within this defined concentration range of SCFAs, butyrate proportion up to 50% further promoted TJ function. Applying this result to dietary fiber selection, certain rapidly fermenting fibers may generate a high amount of SCFA that may harm gut barrier. Slow fermenting fibers that deliver appropriate concentrations of SCFAs to the epithelium with high proportion of butyrate might improve barrier function.