Dietary convergence induces individual responses in faecal microbiome composition

Area of Science:

• Human Gut Microbiome Research
• Nutritional Science
• Microbial Ecology

Background:

• Dietary variation significantly influences gut microbiome composition.
• Assessing dietary impact is challenging due to confounders and methods.
• This study investigates dietary convergence's effect on Western gut microbiota.

Purpose of the Study:

• To quantify the impact of reduced dietary variation on fecal microbiota composition.
• To analyze changes in microbial community types and abundance.
• To determine if dietary restriction leads to microbial community convergence.

Main Methods:

• 18 healthy volunteers consumed a restricted diet (oat flakes, milk, water) for 6 days.
• Daily fecal samples analyzed using 16S rRNA sequencing and flow cytometry.
• Transit time and blood parameters were monitored.

Main Results:

• Restricted diet increased Bacteroides prevalence but decreased overall microbial load and Faecalibacterium abundance.
• No significant reduction in inter- or intra-individual microbial variation was observed.
• The intervention showed a small effect size (3.4%) on genus-level differentiation, with high individual variability.

Conclusions:

• Dietary variation significantly impacts Western gut microbiota, though the effect size is limited.
• Individual responses to dietary changes are substantial.
• Dietary convergence does not consistently lead to convergence of fecal microbial communities.