The pasteurised paradox: why dead bacteria worked better than live ones

There is a detail about Akkermansia muciniphila that surprises almost everyone the first time they hear it. In the research, the pasteurised form, meaning heat-treated, non-living bacteria, worked at least as well as the live form, and in the human trial rather better. For a category built on the idea of "live cultures," that takes some explaining.

The clue from the lab

In 2017, Hubert Plovier and colleagues set out to understand how Akkermansia improves metabolism. Working in obese and diabetic mice, they found that a single protein from the bacterium's outer membrane, later studied as Amuc_1100, reproduced much of the metabolic benefit on its own. The pasteurised bacterium worked at least as well as the live one (Plovier et al., 2017).

The reason heat-killing does not ruin things is structural. If the active component is a protein fixed to the cell surface, the bacterium does not need to be alive to present it. Pasteurisation stops the cells being viable and leaves those surface proteins in place. You keep the part that matters. What you lose is the unpredictability of administering a living organism, which for something sold in a capsule is no small thing.

The first human trial

Two years later the idea was tested in people. Clara Depommier and colleagues ran the first human study of Akkermansia supplementation: 32 overweight, insulin-resistant adults took live Akkermansia, pasteurised Akkermansia, or a placebo every day for three months (Depommier et al., 2019).

The primary goal was safety, and on that both forms passed: well tolerated, no significant adverse effects. The metabolic markers told the more interesting story. The group taking the pasteurised form showed the clearest improvements, including in insulin sensitivity and several markers of metabolic health, while the live form did not separate from placebo as cleanly.

The regulatory consequence

This is the foundation of how Akkermansia is sold legally in Europe. In 2022, the European Union authorised pasteurised Akkermansia muciniphila as a Novel Food: the heat-treated, non-living form, the same one studied by Depommier and colleagues. The live form does not hold that authorisation as a food supplement.

Vekovia uses the pasteurised form for that reason. It is the version with the human data behind it, and the version the authorisation covers. Vekovia · Bilberry is made with it, as is every other Akkermansia capsule in the range.

Where the science is now

The 2019 trial was small and exploratory, and its authors said so plainly. The work has continued since. In 2025, a larger trial published in Cell Metabolism extended the research into people with type 2 diabetes (Zhang et al., 2025).

This is early science, and we describe it rather than promise outcomes from it. What makes the pasteurised paradox worth telling is how cleanly it resolved: a mouse experiment predicted which form would matter, and the first human trial came out the same way.