Resistant Starches Types 2 and 4 Have Differential Effects on the Composition of the Fecal Microbiota in Human Subjects

Abstract

BackgroundTo systematically develop dietary strategies based on resistant starch (RS) that modulate the human gut microbiome, detailed in vivo studies that evaluate the effects of different forms of RS on the community structure and population dynamics of the gut microbiota are necessary. The aim of the present study was to gain a community wide perspective of the effects of RS types 2 (RS2) and 4 (RS4) on the fecal microbiota in human individuals.Methods and FindingsTen human subjects consumed crackers for three weeks each containing either RS2, RS4, or native starch in a double-blind, crossover design. Multiplex sequencing of 16S rRNA tags revealed that both types of RS induced several significant compositional alterations in the fecal microbial populations, with differential effects on community structure. RS4 but not RS2 induced phylum-level changes, significantly increasing Actinobacteria and Bacteroidetes while decreasing Firmicutes. At the species level, the changes evoked by RS4 were increases in Bifidobacterium adolescentis and Parabacteroides distasonis, while RS2 significantly raised the proportions of Ruminococcus bromii and Eubacterium rectale when compared to RS4. The population shifts caused by RS4 were numerically substantial for several taxa, leading for example, to a ten-fold increase in bifidobacteria in three of the subjects, enriching them to 18–30% of the fecal microbial community. The responses to RS and their magnitudes varied between individuals, and they were reversible and tightly associated with the consumption of RS.ConclusionOur results demonstrate that RS2 and RS4 show functional differences in their effect on human fecal microbiota composition, indicating that the chemical structure of RS determines its accessibility by groups of colonic bacteria. The findings imply that specific bacterial populations could be selectively targeted by well designed functional carbohydrates, but the inter-subject variations in the response to RS indicates that such strategies might benefit from more personalized approaches.

Modulation of the gut microbiota by prebiotic fibres and bacteriocins

“…in the gut, while type 2 resistant starch increases Ruminococcus bromii and Eubacterium rectale spp. in humans and Bifidobacterium , Akkermansia and Allobaculum genera in mice [4,52,53]. Type 3 resistant starch is considered the most resistant form of resistant starch [54].…”

Human gut microbiota: does diet matter?

“…), resistant starch (stimulates bifidobacteria, Bacteroides spp., Ruminococcus bromii, E. rectale and Roseburia spp. ), β-glucan (stimulates bifidobacteria) and fructan (stimulates bifidobacteria, Bacteroides spp., lactobacilli and butyrate-producers) are well recognised (144,(154)(155)(156)(157)(158)(159)(160)(161) . In addition, arabinoxylan-oligosaccharides, which are enzymatic hydrolysis products of arabinoxylan, have been shown to stimulate the growth of bifidobacteria in some studies (156) .…”

Nonalcoholic Fatty Liver Disease, the Gut Microbiome, and Diet

“…), and Verrucomicrobia (A. muciniphilia) while decreasing Firmicutes (100-102). Also, in humans, the administration of RS has been shown to induce phylum-level changes, selectively increasing numbers of Actinobacteria and Bacteroidetes and reducing Firmicutes; at the species level, an increase in Bifidobacterium adolescentis, E. rectale, Roseburia spp., and R. bromii have been reported (103)(104)(105)(106)(107). These various bacteria differ significantly in the production of metabolic byproducts and potential interactions with the host.…”