Abstract
Dietary fibres consist of carbohydrate polymers of plant origin and are neither digested nor absorbed in the small intestine. They have at least one functional property linked to stools production, colonic fermentation, cholesterol, glucose or insulin levels. Different models are available to investigate the prebiotic potential of such a molecule. The aim of this study was to compare our clinical data with three previously unpublished preclinical studies, all looking for prebiotic activity of a medium-chain arabinoxylan (MC-AX) extracted from wheat endosperm. MC-AX was tested in an in vitro multicompartment digestive system (SHIME®), piglet and rat models as well as a clinical study, at doses ranging from 1 to 10g/day and exposed for 2 to 4 weeks. Selected bacterial counts and metabolites were measured at different time points. MC-AX induced an increase in Bifidobacterium in treated groups compared to placebo of at least one log unit in all models. This could be measured as early as 7 days (SHIME®) with the strongest variation observed in piglets (2 logs) at day 14. We observed a significant decrease in acetate production, balanced by an increase in both propionate and butyrate in the rodent and human studies. While there are some quantitative differences between the models, partially due to dose or species specificities, there is a clear and consistent overall pattern. Data were also compared to published clinical trials on dietary fibres to explain some structure-activity relationships relative to their physicochemical properties.