A vegan or vegetarian diet substantially alters the human colonic faecal microbiota

Paul Enck (1) , Bettina Lange (1) , Jasmin Zimmer (1) , Julia-Stefanie Frick (1) , Helene Sauer (1) , Kurt Zimmermann (1) , Andreas Schwiertz (1) , Kerstin Rusch (1) , Sibylle Klosterhalfen (1)

1 Psychosomatic Medicine and Psychotherapy

Background/Objectives: Consisting of ~ 1014 microbial cells, the intestinal microbiota represents the largest and most complex microbial community inhabiting the human body. However, the influence of regular diets on the microbiota is widely unknown. Subjects/Methods: We examined faecal samples of vegetarians (n=144), vegans (n=105) and an equal number of control subjects consuming ordinary omnivorous diet who were matched for age and gender. We used classical bacteriological isolation, identification and enumeration of the main anaerobic and aerobic bacterial genera and computed absolute and relative numbers that were compared between groups. Results: Total counts of Bacteroides spp., Bifidobacterium spp., E. coli, and Enterobacteriaceae spp. were significantly lower (p=.001, p=.002, p=.006 and p=.008, resp) in the vegan samples compared to controls while others (E. coli biovars, Klebsiella spp., Enterobacter spp., other Enterobacteriaceae, Enterococcus spp., Lactobacillus spp., Citrobacter spp. and Clostridium spp.) were not. Subjects on a vegetarian diet ranked between vegans and healthy controls. The total microbial count did not differ between the groups and subgroups. In addition, subjects on a vegan or vegetarian diet showed significantly (p=.0001) lower stool pH than controls, and stool pH and counts of E. coli and Enterobacteriaceae were significantly correlated across all subgroups. Conclusion: Maintaining a strict vegan or vegetarian diets results in a significant shift in the microbiota while the total cell numbers remains unaltered.

Mots clés: vegan; vegetarian; diet; microflora

Domaines: Alimentation et Nutrition

Paul Enck, Bettina Lange, Jasmin Zimmer, Julia-Stefanie Frick, Helene Sauer, et al.. A vegan or vegetarian diet substantially alters the human colonic faecal microbiota. European Journal of Clinical Nutrition, 2011, ⟨10.1038/ejcn.2011.141⟩. ⟨hal-00665871⟩