In nearly 1,500 younger and midlife adults, an older-looking brain lined up with gut bacteria and weaker memory

What the research found

Study (cross-sectional brain scans, plus stool in one group). ScienceDaily carried the UCLA Health account on 4 October 2026. Kanhao Zhao, Arpana Church, and colleagues report in eBioMedicine (2026; 132:106468; doi 10.1016/j.ebiom.2026.106468). The paper title describes young and mid-life adults. Resting scans from nearly 1,500 people in three groups were used to estimate brain age from how regions communicate. The gap versus chronological age was called the Brain Aging Index. Across the groups, a higher index lined up with worse working memory and executive function and with more depression symptoms. In one group, stool samples linked a higher index to particular gut bacteria and metabolites, including some fat molecules, a cholesterol-related compound, and lower estetrol. The release does not split results by sex and does not give a hazard ratio or a treatment. Church said the signals may be detectable decades before obvious symptoms, and that targeting the gut is a hypothesis, not a program tested here. Educational notes. This is not a dementia test or a diet prescription.

Evidence level: Human study. A study in people, but an association isn't proof of cause.

Read the original at UCLA Health / eBioMedicine