Changes in Gut Microbiota after a Four-Week Intervention with Vegan vs. Meat-Rich Diets in Healthy Participants: A Randomized Controlled Trial

Abstract

An essential role of the gut microbiota in health and disease is strongly suggested by recent research. The composition of the gut microbiota is modified by multiple internal and external factors, such as diet. A vegan diet is known to show beneficial health effects, yet the role of the gut microbiota is unclear. Within a 4-week, monocentric, randomized, controlled trial with a parallel group design (vegan (VD) vs. meat-rich (MD)) with 53 healthy, omnivore, normal-weight participants (62% female, mean 31 years of age), fecal samples were collected at the beginning and at the end of the trial and were analyzed using 16S rRNA gene amplicon sequencing (Clinical Trial register: DRKS00011963). Alpha diversity as well as beta diversity did not differ significantly between MD and VD. Plotting of baseline and end samples emphasized a highly intra-individual microbial composition. Overall, the gut microbiota was not remarkably altered between VD and MD after the trial. Coprococcus was found to be increased in VD while being decreased in MD. Roseburia and Faecalibacterium were increased in MD while being decreased in VD. Importantly, changes in genera Coprococcus, Roseburia and Faecalibacterium should be subjected to intense investigation as markers for physical and mental health.

A Vegan Diet Is Associated with a Significant Reduction in Dietary Acid Load: Post Hoc Analysis of a Randomized Controlled Trial in Healthy Individuals

“…The present study is a post hoc analysis of a randomized controlled trial we reported earlier [ 19 ]. The study design has been described elsewhere in detail [ 19 , 20 ]. In brief, we initially performed a monocentric, randomized-controlled pilot trial with parallel group design at the Center for Complementary Medicine at Freiburg University, Germany.…”

Analysis of S-Adenosylmethionine and S-Adenosylhomocysteine: Method Optimisation and Profiling in Healthy Adults upon Short-Term Dietary Intervention

“…Regardless of personal motivations, which may include mitigation of climate change and food insecurity, animal welfare, and health improvement, the study of metabolism and disease prevention in such dieters has gained growing interest, especially in pediatric and adolescent populations [ 32 , 33 , 34 , 35 ]. We employed our method for the assessment of SAM and SAH concentrations in a well-characterised cohort of healthy adults [ 36 , 37 , 38 , 39 ]. Of note, samples of plasma in this cohort were isolated and immediately frozen at −80 °C, without acidification prior to freezing.…”

“…We hypothesized that SAM and SAH concentration in human plasma may vary upon transition from an omnivorous diet into a vegan or meat-rich diet. To test the effect of a plant-based diet on SAM and SAH metabolism, we examined SAM and SAH concentrations in the plasma and urine of a well-characterised cohort of healthy omnivorous adults participating in a randomised controlled trial (RCT) with an intervention with either a vegan or a meat-rich diet (VD and MD, respectively) for 4 weeks [ 36 , 37 , 38 , 39 ]. Our study revealed similar variations in SAM and SAH concentrations from baseline to end of trial in the plasma and urine of healthy adults, regardless of dietary pattern.…”

Bowel Health in U.S. Vegetarians: A 4-Year Data Report from the National Health and Nutrition Examination Survey (NHANES)

“…Plant-based diets (including vegetarian and vegan diets), in contrast, are rich in fiber-dense foods, including fruits, legumes and green leafy vegetables [ 10 ]. These diets influence gut motility and the composition of the human gut microbiota [ 11 , 12 , 13 , 14 ]. Although studied less frequently, several trials also suggested differences in defecation and stool patterns between vegetarians and non-vegetarians [ 11 ].…”