What are postbiotics?
You know probiotics. You may know prebiotics. Postbiotics are the newest member of the family — and the one a fresh fermented food is unusually good at delivering.
The definition
In 2021, the International Scientific Association for Probiotics and Prebiotics (ISAPP) set a consensus definition:
A preparation of inanimate microorganisms and/or their components that confers a health benefit on the host.
In plain English: postbiotics are the beneficial compounds and inactivated microbial parts left behind by fermentation — not the live bugs themselves.
The 'biotics' family, quickly
- Probiotic — live microbes that, in adequate amounts, confer a benefit.
- Prebiotic — a substrate your microbes use (fuel for the flora).
- Synbiotic — live microbes plus a substrate, working together.
- Postbiotic — inanimate microbes and/or their components that confer a benefit.
Why a long ferment matters
A long, controlled ferment doesn't just grow live cultures — it generates postbiotics along the way: short-chain fatty acids (butyrate, propionate, acetate), bioactive peptides, exopolysaccharides, and cell-wall fragments. These have been studied in connection with the gut barrier, immune signalling, and metabolism.
Here's the useful part: postbiotics are set at production and relatively stable. So even as live counts settle in the jar, the postbiotic layer keeps doing its job. It's the honest answer to the one real objection to probiotics — "are they still alive when I eat them?" — because postbiotics don't need to be.
This is why a fresh cultured yogurt can tell a "probiotics and postbiotics" story that a shelf-stable capsule can't fully match.
Read the deeper science, see capsules vs. fermented food, or find your mix.
These statements have not been evaluated by the Food and Drug Administration. This content is general wellness information, not medical advice.