Higher Midlife Vitamin D Linked to Lower Brain Tau Levels

A new study has found that higher vitamin D levels in early midlife are associated with lower levels of tau protein in the brain nearly two decades later, a marker linked to Alzheimer's disease and dementia. Researchers analyzed data from 793 adults, who were an average of 39 years old and free of dementia at the start, as part of the Framingham Heart Study. Vitamin D concentrations were measured in blood samples taken between 2002 and 2005, with levels above 30 nanograms per milliliter classified as high and those below as low. Approximately 16 years later, participants underwent positron emission tomography scans to assess tau and amyloid beta proteins, both hallmarks of Alzheimer's pathology.

The results, published in Neurology Open Access, showed that individuals with higher vitamin D levels had significantly reduced tau accumulation in their brains, including in regions affected early by Alzheimer's. No such link appeared with amyloid beta levels, suggesting vitamin D may influence specific pathways in brain aging. About 34 percent of participants had low vitamin D at baseline, and only 5 percent reported taking supplements.

"This study is the first to our knowledge...