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Multidomain Lifestyle Program Reshapes Gut Bacteria In Older Adults At Dementia Risk

A South Korean trial links a diet, exercise and brain-training program to gut bacteria changes tied to better cognitive scores in at-risk seniors.

By Dr. Axe Editorial Team · October 23, 2026 · 1 source · Watch

Photo: Pexels

A 24-week multidomain lifestyle program reshaped the community of microbes living in the gut of older adults at risk of dementia, according to a sub-study of the SUPERBRAIN trial published October 12, 2026 in BMC Geriatrics.

91on program, 39 controls

24-weektrial

19genera shifted

Researchers followed 130 adults aged 60 to 79 with at least one modifiable dementia risk factor, 91 in a 24-week multidomain lifestyle intervention combining diet, exercise and cognitive training, and 39 controls. Stool samples were sequenced at the start and at week 24, with cognitive performance measured by a standard neuropsychological test battery. The intervention group showed greater improvement in total cognitive scores than controls. Within that group, gut bacteria diversity decreased over 24 weeks while the overall bacterial community pattern shifted significantly; neither changed in controls. A dysbiosis index, tracking drift from a healthy reference pattern, dropped in the intervention group but not controls. Nineteen bacterial genera changed consistently, including enrichment of short-chain fatty acid producers such as Faecalibacterium and Butyrivibrio, and reductions in Enterobacteriaceae, a family that includes several potentially harmful bacteria.

The authors say these shifts represent movement toward a healthier reference microbiome configuration, with changes in several genera tracking changes in cognitive and clinical measures. Short-chain fatty acids are compounds gut bacteria make by fermenting fiber, and they can influence inflammation and the gut lining. A model combining baseline gut bacteria and physical function data predicted who would improve, with an area under the curve of 0.83, and baseline physical performance plus one genus, Eubacterium, as the strongest contributors.

0.83AUC

predictive accuracy of a model combining baseline gut microbiome and physical function data for forecasting which of the 91 intervention participants would show cognitive improvement

BMC Geriatrics, 2026, Yoon et al.

This sub-study bundled diet, exercise and cognitive training together, so the microbiome shifts cannot be separated from each component's own effect. The authors call the findings exploratory and say larger, independently validated studies are needed.

Dr. Axe’s Take

This fits what I'd expect: a real lifestyle overhaul, diet, movement and mental engagement together, moves the gut community in a favorable direction alongside better cognitive scores. The drop in Enterobacteriaceae and rise in short-chain-fatty-acid producers like Faecalibacterium lines up with what we know about fiber feeding beneficial microbes that support the gut lining and calm inflammation reaching the brain. I wouldn't wait on a bacteria pill. This week, build meals around fiber-rich vegetables, legumes and fermented foods, and pair that with daily movement and something mentally challenging, a language, an instrument, a puzzle. No single piece works alone -- diet, movement and mental challenge need to happen together.

— Dr. Axe

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Story summary

Who: 130 adults ages 60-79 with a dementia risk factor; 91 intervention, 39 controls
Design: Sub-study of controlled trial; stool and cognitive testing at baseline, week 24
Dose: 24-week program: diet, exercise, cognitive training, related components
Primary result: Intervention group had greater cognitive improvement; dysbiosis index fell only in that group
Secondary: 19 genera shifted, more Faecalibacterium/Butyrivibrio, less Enterobacteriaceae; prediction model AUC 0.83
Funding / conflicts: Funded by the Korea Dementia Research Center, the Ministry of Health and Welfare and Ministry of Science and ICT of Republic of Korea, the National Research Council of Science and Technology, the Institute of Information and Communications Technology Planning and Evaluation, and the National Research Foundation of Korea. The authors declare no competing interests.
Date: Oct 12, 2026