Why are postbiotics attracting growing attention across the health and nutrition sector?

The Cell Metabolism review “Unlocking the power of postbiotics” highlights a significant shift in microbiome science. Researchers increasingly recognise that many of the health effects historically attributed to probiotics may be mediated by the bioactive compounds they produce, now broadly referred to as postbiotics.

From living bacteria to what they leave behind

Zhao and colleagues describe postbiotics as preparations of inanimate microorganisms or their components. The review brings together work on bacteria and yeasts and is candid about a gap in the field: much of what is known about specific postbiotic molecules was learned in probiotic studies, and several of the proposed pathways remain speculative. The authors write the review explicitly to redirect research attention toward the postbiotic fraction itself.

Four mechanisms in focus

Across the studies reviewed, four modes of action come up repeatedly.

Antioxidant activity — Reducing oxidative stress in cells and tissues.

Immune regulation — Modulating innate and adaptive immune responses.

Microbiota modulation — Shaping the composition of the resident gut community.

Barrier function — Supporting epithelial tight junctions in the gut lining.

Why stability changes the conversation

The effects described resemble those of probiotics. What sets postbiotics apart, according to the authors, is stability and safety. A postbiotic does not need to stay alive, so it is not exposed to the viability losses that live cultures face during processing, heat treatment and storage.

For formulators this is a practical point, not an abstract one. It opens up shelf-stable formats, ambient distribution and applications such as UHT beverages, where live cultures struggle. It also changes the quality question: the relevant measure becomes retention of functional markers, not colony counts.

Humans and animals in one framework

The review treats human and animal nutrition side by side. In animal science it covers applications such as yeast fermentation products in dairy cattle, with reported effects on milk production and feed efficiency. The authors also position postbiotics as part of the effort to reduce antibiotic use in livestock farming, while supporting health and productivity.

What the review does not settle

Much of the underlying evidence comes from cell and animal models. The authors note that laboratory conditions cannot fully replicate the changing environment of the gut, and that the function of a postbiotic depends heavily on the source organism and the way it is produced. Two postbiotic ingredients are therefore not interchangeable, and each needs to be characterised on its own terms.