Research
Mixed
Dietary interventions produce observable changes in gut microbiome composition within days, whereas microbiome-mediated effects on host phenotypes or biomarkers require interventions lasting weeks to months.
If you change your diet, your gut bacteria will likely adapt within a few days. However, do not expect to feel health benefits or see changes in blood markers immediately. You need to maintain the dietary change for several weeks or months to see the downstream health effects driven by those microbial changes.
GoodConditionalHIGH confidence
We find evidence that direct effects of diet on the microbiome are likely to be observable within days, while the length of an intervention required for observing microbiome-mediated effects on the host phenotype or host biomarkers, depending on the outcome, may be much longer, on the order of weeks or months.
Why this rating
The paper is a review citing multiple studies (refs 6, 46, 62, 63) and general consensus in the field, though it notes mechanisms are not fully characterized.
Source
A Guide to Diet-Microbiome Study Design
Abigail J. Johnson et al. · Frontiers in Nutrition · 2020
narrative_reviewCited 152×
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