A fibre-eating gut bacterium that makes a beneficial fat which fuels the gut lining. Its presence is linked to greater muscle strength, and it grows scarcer with age. The strongest evidence comes from animals; human data show links, not proof, and no product exists. For now, a fibre-rich diet is the realistic way to support it. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Stool Roseburia / butyrate-producer abundance | Present and stable-to-rising relative abundance | Confirms the target population is present and responding |
| Stool short-chain fatty acids (incl. butyrate) | Butyrate in the mid-to-upper reference range | Reflects functional output of butyrate producers |
| hs-CRP | Below 1.0 mg/L | Tracks low-grade inflammation the gut barrier influences |
| HbA1c | Below 5.4% | Screens for the metabolic health the species is associated with |
| Fasting glucose | 75–86 mg/dL | Complements HbA1c for glucose regulation |
| Handgrip strength | At or above age- and sex-referenced norms | Functional readout of the species' headline proposed benefit |
Cadence: Baseline before starting; reassess ~3 months after a consistent change, then every 6–12 months