This photomicrograph of a Gram-stained specimen shows numerous diplococcal, Gram-negative Neisseria flavescens bacteria. Image credit: Dr W.A. Clark / CDC (Public Domain).
A bacterium commonly found in the human mouth could provide some clues to healthier ageing, according to new research published in Nature Ageing.
The study led by Jiawei Chen and colleagues identified Neisseria flavescens as a microorganism associated with slower biological ageing in humans. The findings add to growing interest in the role of the oral microbiome and how bacteria in the mouth might affect health beyond the teeth and gums.
In order to investigate the connection, the researchers used an artificial intelligence-based framework called AURORA to analyse biological and microbiome data. Their analysis pointed to N. flavescens as a possible contributor to healthier ageing.
Laboratory experiments offered some further clues. When live bacteria were given to Caenorhabditis elegans, a small roundworm commonly used in ageing research, the animals lived longer and enjoyed an extended healthspan. Healthspan refers to the time spent in relatively good health.
Experiments in older mice produced other interesting results. Animals treated with heat-killed preparations of the bacterium showed changes in blood metabolites, liver gene activity and gut microbiome composition. Some of these changes resembled patterns more commonly seen in younger animals.
Researchers have also identified two strains of the bacterium that produced metabolites that are potentially beneficial to health, and these substances may help explain some of the effects observed in the experiments.
But there are reasons to be cautious though, as the human findings show an association, it is not proof that the bacterium actually slows ageing. Also, the benefits that are seen in worms and mice also need to be tested in people before any health claims can be made.
So for now, maintaining good oral health is worthwhile. Brushing twice a day and cleaning between the teeth, and avoiding tobacco, are all sensible steps. Taking unverified bacterial supplements to try to slow ageing isn't recommended.
This research opens an interest in studying N. flavescens further, and it is necessary to have clinical trials first in order to establish whether N. flavescens can genuinely help people stay healthier for longer.
Reference
Chen, J. et al. (2026). Multi-modality profiling identifies Neisseria flavescens as a central geroprotective oral commensal in humans. Nature Ageing https://doi.org/10.1038/s43587-026-01220-0
