Variable responses of human microbiomes to dietary supplementation with resistant starch

Abstract

BackgroundThe fermentation of dietary fiber to various organic acids is a beneficial function provided by the microbiota in the human large intestine. In particular, butyric acid contributes to host health by facilitating maintenance of epithelial integrity, regulating inflammation, and influencing gene expression in colonocytes. We sought to increase the concentration of butyrate in 20 healthy young adults through dietary supplementation with resistant starch (unmodified potato starch—resistant starch (RS) type 2).MethodsFecal samples were collected from individuals to characterize butyrate concentration via liquid chromatography and composition of the microbiota via surveys of 16S rRNA-encoding gene sequences from the Illumina MiSeq platform. Random Forest and LEfSe analyses were used to associate responses in butyrate production to features of the microbiota.ResultsRS supplementation increased fecal butyrate concentrations in this cohort from 8 to 12 mmol/kg wet feces, but responses varied widely between individuals. Individuals could be categorized into three groups based upon butyrate concentrations before and during RS: enhanced, high, and low (n = 11, 3, and 6, respectively). Fecal butyrate increased by 67 % in the enhanced group (from 9 to 15 mmol/kg), while it remained ≥11 mmol/kg in the high group and ≤8 mmol/kg in the low group. Microbiota analyses revealed that the relative abundance of RS-degrading organisms—Bifidobacterium adolescentis or Ruminococcus bromii—increased from ~2 to 9 % in the enhanced and high groups, but remained at ~1.5 % in the low group. The lack of increase in RS-degrading bacteria in the low group may explain why there was no increase in fecal butyrate in response to RS. The microbiota of individuals in the high group were characterized by an elevated abundance of the butyrogenic microbe Eubacterium rectale (~6 % in high vs. 3 % in enhanced and low groups) throughout the study.ConclusionsWe document the heterogeneous responses in butyrate concentrations upon RS supplementation and identify characteristic of the microbiota that appear to underlie this variation. This study complements and extends other studies that call for personalized approaches to manage beneficial functions provided by gut microbiomes.

Microbiota, metabolome, and immune alterations in obese mice fed a high‐fat diet containing type 2 resistant starch

“…Moreover, the finding that few intestinal metabolites and host responses were correlated with individual bacterial taxa indicates that there is either a redundancy in metabolic and biosynthetic responses to RS among bacterial species, or alternatively, that there are complex community‐level, metabolic interactions in the intestine that are not related to individual, dominant bacterial genera. This outcome is consistent with human studies on fermentable fibers . Responses of the gut microbiota to such dietary interventions are likely ultimately dependent on the baseline composition and the redundancy of metabolic pathways in multiple bacterial taxa.…”

Role of the intestinal mucosa in acute gastrointestinal GVHD

“…Clinical strategies to increase intestinal butyrate levels are in active development. For example, preclinical evidence suggests potato-based starches can induce production of butyrate from the microbiota, 94 and a randomized trial of this prebiotic for acute GVHD prevention is underway (www. clinicaltrials.gov: NCT02763033).…”

Investigation of carryover effect of prior fibre consumption on growth, serum and tissue metabolic markers in Ossabaw pigs fed a high‐fat diet

“…Fibre consumption is associated with metabolic and health benefits in humans and animals (Holscher ), but the mechanistic basis of these effects is still poorly understood. Effects of fibre are highly influenced by the type consumed, being primarily mediated by effects on the microbiome and fermentation products (Canfora et al., ; Cheng et al., ; Venkataraman et al., ), and effects of these on the host. Inulin and cellulose are two major fibre types that are used in human diets for their digestive and metabolic health benefits (Ahmed & Rashid, ; Buddington, Kapadia, Neumer, & Theis, ; Morowitz et al., ).…”