A longitudinal Swedish study tracked nearly 1,900 older adults over 8 years and found that following an anti-inflammatory dietary pattern significantly reduced dementia risk — even among those already showing early Alzheimer's-related biomarkers in their blood. Participants with elevated phosphorylated tau-217 (p-tau217), a key Alzheimer's marker, had a 29% lower dementia risk if they ate a less inflammatory diet. Those with elevated neurofilament light chain (NfL) and GFAP also showed meaningful risk reductions. People with elevated p-tau217 who adhered more closely to anti-inflammatory eating also lived nearly a full year longer without dementia. The findings suggest dietary quality remains a powerful modifiable factor even after early biological warning signs of neurodegeneration have already emerged.