Differential Influence of Soluble Dietary Fibres on Intestinal and Hepatic Carbohydrate Response

Abstract

Refined foods are commonly depleted in certain bioactive components that are abundant in ‘natural’ (plant) foods. Identification and addition of these ‘missing’ bioactives in the diet is, therefore, necessary to counteract the deleterious impact of convenience food. In this study, multiomics approaches were employed to assess the addition of the popular supplementary soluble dietary fibers inulin and psyllium, both in isolation and in combination with a refined animal feed. A 16S rRNA sequencing and 1H NMR metabolomic investigation revealed that, whilst inulin mediated an increase in Bifidobacteria, psyllium elicited a broader microbial shift, with Parasutterella and Akkermansia being increased and Enterorhabdus and Odoribacter decreased. Interestingly, the combination diet benefited from both inulin and psyllium related microbial changes. Psyllium mediated microbial changes correlated with a reduction of glucose (R −0.67, −0.73, respectively, p < 0.05) and type 2 diabetes associated metabolites: 3-methyl-2-oxovaleric acid (R −0.72, −0.78, respectively, p < 0.05), and citrulline (R −0.77, −0.71, respectively, p < 0.05). This was in line with intestinal and hepatic carbohydrate response (e.g., Slc2a2, Slc2a5, Khk and Fbp1) and hepatic lipogenesis (e.g., Srebf1 and Fasn), which were significantly reduced under psyllium addition. Although established in the liver, the intestinal response associated with psyllium was absent in the combination diet, placing greater significance upon the established microbial, and subsequent metabolomic, shift. Our results therefore highlight the heterogeneity that exists between distinct dietary fibers in the context of carbohydrate uptake and metabolism, and supports psyllium containing combination diets, for their ability to negate the impact of a refined diet.

Addition of Soluble Fiber in Low-Fat Purified Diets Maintains Cecal and Colonic Morphology, Modulates Bacterial Populations and Predicted Functions, and Improves Glucose Tolerance Compared with Traditional AIN Diets in Male Mice

“…Previous data suggest that CEL is important for age-related diversification of the intestinal microbiota ( 32 ), and thus our results indicate that it may be better to continue including CEL in future designs of PDs. In fact, a recent study suggested that adding IN to a lower-fat diet containing CEL tended to increase alpha diversity relative to CEL alone, suggesting the importance of maintaining CEL to preserve species richness ( 33 ). Beta-diversity analysis indicated that each fiber type (GBDs, CEL based, or soluble-fiber based) supported distinctly different communities of bacteria, regardless of fiber dose.…”

Addition of soluble fiber in low fat purified diets improves gut and metabolic health compared to traditional AIN diets

“…Previous data suggest that cellulose is important for age-related diversification of the intestinal microbiota (29) and thus our results indicate that it may be better to continue including cellulose in future designs of PD. In fact, a recent study suggested that adding inulin to a lower fat diet containing cellulose tended to increase alpha diversity relative to cellulose alone, suggesting the importance of maintaining cellulose to preserve species richness (30). Beta diversity analysis indicated that each fiber type (GBDs, cellulose based, or soluble fiber based) supported distinctly different communities of bacteria, regardless of fiber dose.…”

Anti-Aging Effect of Dietary Fiber Compound Mediated by Guangxi Longevity Dietary Pattern on Natural Aging Mice

“…Currently, most studies on dietary fiber have focused on the dietary fiber in a specific food or on a pure substance, such as pectin [ 8 ], inulin [ 9 ], etc. The beneficial effects of different dietary fibers after mixing have also been explored [ 10 , 11 ], but no studies have been found to report on the effects of dietary pattern-mediated characteristic dietary fiber compound (CDFC) on healthy aging.…”