Fermented foods and the microbiome: what a small trial can tell us.
An interesting dietary-pattern study, not a natto-only experiment.
By Happy Natto · Updated September 17, 2026
Illustrative editorial photograph. It is not an image from the cited study.Photo: alleksana / Pexels
A small study compared a high-fiber dietary intervention with a fermented-food intervention. In the fermented-food arm, researchers observed greater microbial diversity and changes in selected inflammatory markers.
What it does not establish
The intervention involved a range of fermented foods, not natto alone. Sample size, study duration and marker-based outcomes limit conclusions about disease prevention or a benefit from one specific food.
How to use this entry
Open the original source for the full methods, analyses and context. The evidence label describes the type of source, not a universal score for the healthfulness of natto. We do not turn a product link into a medical recommendation.
