Diet patterns
The microbes, diet by diet
Landmark study21,561 people in 5 cohorts, by the diet they said they follow: 19,817 omnivores, 1,088 vegetarians and 656 vegans (Fackelmann 2025). Comparing omnivores with vegans, 44 of our microbes are higher in omnivores, and 25 in vegans; 190 more show very small differences.
An association the authors report, measured once per person. It doesn’t mean a diet changes this microbe, or that the microbe affects health.
Higher in omnivores 39
Biggest difference first · omnivores vs vegans
Streptococcus thermophilus Higher in 5 of 5 cohorts
Lawsonibacter asaccharolyticus Higher in 5 of 5 cohorts
[Ruminococcus] torques Higher in 5 of 5 cohorts
Bilophila wadsworthia Higher in 5 of 5 cohorts
Alistipes putredinis Higher in 4 of 5 cohorts
1,025 more of our microbes were compared with no clear difference, or only in one cohort.
“Higher” is the study’s measure: on average, a bigger share of gut bacteria across everyone in the group, carriers or not. It isn’t how many people carry it.
Only results the authors call clear (q under 0.1) that come from at least 2 of the 5 cohorts. Differences under the usual size for a small one (a standardized difference under 0.2) don't lead the lists: they're folded, labeled. Their table lists 3,469 microbes for this pair; 1,294 of the 1,557 with a species name across the study are microbes we list, and the rest have no page here.
Fackelmann G et al., Nature Microbiology 2025, CC BY 4.0 · Supplementary Table 11 · About the study · Data sources