A 16-year study of 793 adults found that people with higher vitamin D levels in midlife had significantly lower levels of tau protein in their brains decades later. Tau is a key biomarker associated with Alzheimer's disease and dementia. Participants with vitamin D levels above 30 ng/mL in their 30s and 40s showed less tau accumulation when brain scanned 16 years later. However, vitamin D levels weren't linked to amyloid beta, another Alzheimer's marker. While the study shows correlation rather than causation, researchers suggest maintaining adequate vitamin D in midlife could be a modifiable risk factor for brain health.
