Women over 55 who have eaten a plant-based diet for years tend to have different gut bacteria than those who eat meat, with more bacteria linked to fiber digestion and fewer linked to animal-based diets.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Whether vegetarian diets consistently associate with Prevotella enrichment and Bacteroides reduction across diverse postmenopausal populations, controlling for confounders like age, BMI, and fiber intake.
A systematic review and meta-analysis of all published cross-sectional and cohort studies comparing gut microbiota in postmenopausal women (≥55 years) following vegetarian vs. omnivorous diets for ≥5 years, using standardized 16S rRNA sequencing and reporting genus-level abundances, with adjustment for BMI, fiber intake, and medication use.
Whether switching from an omnivorous to a vegetarian diet for 12 weeks directly causes an increase in Prevotella and Faecalibacterium and a decrease in Bacteroides in postmenopausal women.
A double-blind, randomized controlled trial of 100 healthy postmenopausal women (60–75 years, BMI 18–24) assigned to either a 12-week vegetarian diet (≥50g fiber/day, no meat/fish/dairy) or a matched omnivorous diet, with fecal samples collected at baseline, week 6, and week 12 for 16S rRNA sequencing to measure genus-level microbial changes as the primary outcome.
Whether women who adopt a vegetarian diet over 5 years develop sustained increases in Prevotella and Faecalibacterium compared to those who remain omnivorous, adjusting for confounders.
A prospective cohort study following 500 postmenopausal women (55–70 years) for 5 years, collecting annual dietary records and fecal samples, comparing microbial shifts in those who transition to vegetarianism versus those who maintain omnivorous diets, with adjustment for age, BMI, antibiotics, and fiber intake.
Whether women with high Prevotella abundance are more likely to have followed a vegetarian diet for ≥5 years than those with low Prevotella.
A case-control study comparing 100 postmenopausal women with high Prevotella abundance (top quartile) to 100 with low abundance (bottom quartile), matched for age and BMI, and retrospectively assessing dietary history over the past 5 years via validated food frequency questionnaires.
Whether a single snapshot of diet and microbiota in postmenopausal women shows a consistent association between vegetarian diet and Prevotella enrichment.
A cross-sectional survey of 200 postmenopausal women (55–75 years) assessing current diet via 7-day food diary and measuring fecal microbiota via 16S rRNA sequencing, comparing Prevotella abundance between vegetarians (≥5 years) and omnivores.