A randomized trial to determine the impact of a digestion resistant starch composition on the gut microbiome in older and mid-age adults.

BACKGROUND: The elderly often have a diet lacking resistant starch (RS) which is thought to lead to gut microbiome dysbiosis that may result in deterioration of gut colonocytes.

OBJECTIVE: The primary objective was to assess if elderly (ELD; ≥ 70 years age) had microbiome dysbiosis compared to mid-age (MID; 30-50 years age) adults and then determine the impact of daily consumption of MSPrebiotic® (a RS) or placebo over 3 months on gut microbiome composition. Secondary objectives included assessment of stool short-chain fatty acids (SCFA) and inflammatory markers in ELD and MID Canadian adults.

DESIGN: This was a prospective, placebo controlled, randomized, double-blinded study. Stool was collected at enrollment and 6, 10 and 14 weeks after randomization to placebo or MSPrebiotic® . Microbiome analysis was done using 16S rRNA sequencing of DNA extracted from stool. SCFA analysis of stool was performed using gas chromatography.

RESULTS: There were 42 ELD and 42 MID participants randomized to either placebo or MSPrebiotic® who completed the study. There was significantly higher abundance of Proteobacteria (Escherichia coli/Shigella) in ELD compared to MID at enrollment (p < 0.001) that was not observed after 12 weeks of MSPrebiotic® consumption. There was a significant increase in Bifidobacterium in both ELD and MID compared to placebo (p = 0.047 and 0.006, respectively). There was a small but significant increase in the stool SCFA butyrate levels in the ELD on MSPrebiotic® versus placebo.

CONCLUSIONS: The study data demonstrated that MSPrebiotic® meets the criteria of a prebiotic and can stimulate an increased abundance of endogenous Bifidobacteria in both ELD and MID without additional probiotic supplementation. MSPrebiotic® consumption also eliminated the dysbiosis of gut Proteobacteria observed in ELD at baseline.

CLINICAL TRIAL REGISTRY NUMBER: NCT01977183 listed on NIH website: ClinicalTrials.gov. The full trial protocol is available on request from the corresponding author.

NUCLEOTIDE SEQUENCE ACCESSION NUMBERS: The 16S rRNA sequencing data and metadata generated in this study have been submitted to the NCBI Sequence Read Archive (SRA: https://www.ncbi.nlm.nih.gov/bioproject/381931).