RBVD study
Previous studies have described benefits and risks on human health associated with a vegan diet. While diet influences the gut microbiota, there is no consensus on the effect of vegan compared to omnivorous diets on the gut microbiota.   We have conducted a pilot study to assess the differences between the gut microbiome of 23 vegans and 23 omnivores (n = 46) in 2017 and 2021 together with more than 300 dietary, lifestyle, and health related characteristics. The fecal microbiome was assessed comparing both 16S rRNA gene amplicon sequencing and metagenome sequencing, to determine robust signals agnostic of sequencing approaches. Dietary grouping itself explained a small but significant proportion of the individual variation between microbiota. Natural clustering of microbiomes explained an even larger proportion, which was mostly explained by enterosignatures and dietary differences (e.g., short-chain fatty acids and micronutrients). We found Ruminococcus torques to be relatively enriched in omnivores across methods and years. Interestingly, this species has been previously associated with unfavorable health outcomes. Despite a low sample size, we found some consistent differences between microbiota of individuals consuming these diets.  While larger cohort studies must verify these results, our results indicate that when methods are robust and relevant dietary, lifestyle and health related characteristics are collected, we can gain understanding of the connection between respective diets and the microbiome and thus possible implications for human health.