Postbiotics

The ISAPP 2021 consensus definition characterises a postbiotic as a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host. The key distinction from probiotics is that postbiotics contain non-viable organisms or isolated microbial components — including cell wall fragments, teichoic acids, exopolysaccharides, secreted proteins, metabolites and extracellular vesicles — without requiring colonisation or survival through the gastrointestinal tract. This gives postbiotics practical advantages in formulation stability, safety in immunocompromised individuals, and defined composition. Pasteurised Akkermansia muciniphila (discussed separately) is one example that fits the ISAPP postbiotic framework. Evidence for specific health effects varies substantially by preparation; most clinical data come from heat-killed Lactobacillus and Bifidobacterium preparations, primarily in infant colic, allergy and mild gastrointestinal complaints. The field is emerging and regulatory frameworks for postbiotic health claims are still developing in most jurisdictions.