Blood biomarkers signal early Alzheimer's risk

Researchers have shown that blood‑based measurements can identify early signs of brain ageing and Alzheimer’s disease. A Lancet‑published study of 1,350 participants found that elevated amyloid‑beta and tau protein levels in blood predicted declines in processing speed, executive function and verbal memory up to five years before clinical symptoms, offering a cheaper alternative to brain scans or spinal‑fluid tests.

In a separate observational study of more than 2,000 Japanese adults, lower plasma vitamin C concentrations were linked to reduced grey‑matter volume and weaker connectivity within the brain’s default‑mode network, both markers associated with cognitive decline. While causality remains unproven, the findings suggest that routine blood tests for protein biomarkers and nutritional factors could help detect Alzheimer’s risk earlier and guide preventive strategies.