Quantification of in Vivo Colonic Short Chain Fatty Acid Production from Inulin

• Published in: Nutrients Vol. 7; no. 11; pp. 8916 - 8929
• Main Authors: Boets, Eef, Deroover, Lise, Houben, Els, Vermeulen, Karen, Gomand, Sara, Delcour, Jan, Verbeke, Kristin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 28.10.2015; MDPI
• Subjects: acetates; Acetates - metabolism; Adult; Bacteria - metabolism; blood sampling; breakfast; butyrates; Butyrates - metabolism; Carbohydrates; Carbon Isotopes - metabolism; Cell cycle; Cholesterol; Colon; Colon - metabolism; Colon - microbiology; Dietary Fiber - metabolism; Fatty acids; Fatty Acids, Volatile - biosynthesis; Fatty Acids, Volatile - metabolism; Fatty Acids, Volatile - pharmacokinetics; Female; Fermentation; Glucose; Humans; intravenous injection; inulin; Inulin - metabolism; Kinases; Liver; Lymphocytes; Male; Metabolism; Nutrition research; Nutritional Status; Propionates - metabolism; propionic acid; Reference Values; short chain fatty acids; stable isotopes; Young Adult; Belgium; inulin; short chain fatty acids; colonic fermentation
• ISSN: 2072-6643; 2072-6643
• DOI: 10.3390/nu7115440

Short chain fatty acids (SCFA), including acetate, propionate, and butyrate, are produced during bacterial fermentation of undigested carbohydrates in the human colon. In this study, we applied a stable-isotope dilution method to quantify the in vivo colonic production of SCFA in healthy humans after consumption of inulin. Twelve healthy subjects performed a test day during which a primed continuous intravenous infusion with [1-13C]acetate, [1-13C]propionate and [1-13C]butyrate (12, 1.2 and 0.6 μmol·kg−1·min−1, respectively) was applied. They consumed 15 g of inulin with a standard breakfast. Breath and blood samples were collected at regular times during the day over a 12 h period. The endogenous rate of appearance of acetate, propionate, and butyrate was 13.3 ± 4.8, 0.27 ± 0.09, and 0.28 ± 0.12 μmol·kg−1·min−1, respectively. Colonic inulin fermentation was estimated to be 137 ± 75 mmol acetate, 11 ± 9 mmol propionate, and 20 ± 17 mmol butyrate over 12 h, assuming that 40%, 10%, and 5% of colonic derived acetate, propionate, and butyrate enter the systemic circulation. In conclusion, inulin is mainly fermented into acetate and, to lesser extents, into butyrate and propionate. Stable isotope technology allows quantifying the production of the three main SCFA in vivo and proved to be a practical tool to investigate the extent and pattern of SCFA production.