Urolithin A: The Walnut Gut Byproduct Tied to a Thicker Brain
Eat a walnut and your gut bacteria turn its ellagitannins into urolithins, compounds that may be tied to how well your brain ages. In a 2-year MRI sub-study of the WAHA trial, bigger rises in urolithin A, urolithin C, and urolithin C glucuronide were associated with preserved cortical thickness among walnut eaters, mostly in right-hemisphere regions. The pattern was stronger in people with metabotype B gut profiles. But this is an association inside a randomized trial, not proof of cause, and it says nothing direct about urolithin A supplements. Here's what the data show, who might care, and who should stay skeptical.
Mouse Study: NR Shifted Aged Brain Cells Toward a Younger State
In a new GeroScience study, 22-month-old mice given nicotinamide riboside (NR) for eight weeks did better on memory and nest-building tests. Their brain immune cells also looked more like those of young mice. This was a mouse study, and it does not show the same benefits in people. The dose was 400 mg/kg, far above what humans take, and the abstract reports only male mice. Here is what changed in the microglia, what the study can't tell us, and what the findings mean for NR users.