Midlife Vitamin D Linked to Lower Tau Buildup Decades Later

An observational study of 793 people found higher midlife vitamin D levels associated with less toxic tau protein in later brain scans.

A study published in Neurology Open Access examined whether vitamin D levels measured in midlife relate to Alzheimer's biomarkers years later. Drawing on 793 participants from the US-based Framingham Heart Study, none with dementia, researchers measured blood vitamin D at an average age of 39. About 16 years later, roughly 430 of them underwent brain PET scans. Higher midlife vitamin D was linked to lower deposits of toxic tau protein. Emer McGrath of the University of Galway is senior author.

The association was specific. No correlation was found between vitamin D and amyloid beta, the other protein commonly tracked in Alzheimer's. The researchers describe their work as among the first to link serum vitamin D to neuroimaging markers of preclinical dementia in midlife adults.

If a cheap, widely available vitamin turned out to influence dementia risk, the implications for accessible prevention would be large. Vitamin D is inexpensive and easy to supplement, which is exactly why a confirmed causal link would matter for populations that cannot afford costly interventions.

But the study is observational and shows only association, not causation. It cannot demonstrate that vitamin D reduces tau formation. A prior French trial of one year of supplementation in adults 70 and older found no effect on tau levels, and the PET group here was smaller than the full sample. The researchers say clinical trials are needed before anyone concludes supplements prevent dementia.

Source: ScienceAlert