Colonic gas homeostasis: Mechanisms of adaptation following HOST-G904 galactooligosaccharide use in humans.

Abstract

We have shown that a galactooligosaccharide prebiotic administration (HOST-G904) initially increased intestinal gas production and this increase declined back to baseline after 2week administration. Our aim was to determine the mechanism of microbiota adaptation; i.e., to determine whether the net reduction is due to decreased overall production or increased gas consumption. In 10 healthy subjects, intestinal gas production and intraluminal disposal was measured before, at the beginning and after 2week of HOST-G904 prebiotic administration. Anal gas was collected for 4 hour after a probe meal. Paired studies were performed without and with high-rate infusion of exogenous gas (24mL/min) into the jejunum to wash-out the endogenous gas produced by bacterial fermentation. The exogenous gas infused was labeled (5% SF6 ) to calculate the proportion of endogenous gas evacuated. The volume of intestinal gas produced i.e., endogenous gas washed-out, increased by 37% at the beginning of HOST-G904 administration (P=.049 vs preadministration) and decreased down to preadministration level after 2week administration (P=.030 vs early administration). The proportion of gas eliminated from the lumen before reaching the anus tended to increase after 2-week administration (87±3% vs 78±5% preadministration; P=.098). Adaptation to regular consumption of HOST-G904 prebiotic involves a shift in microbiota metabolism toward low-gas producing pathways, with a non-significant increase in gas-consuming activity. Hence, regular consumption of HOST-G904 regulates intestinal gas metabolism: less gas is produced and a somewhat larger proportion of it is consumed.