Can More Vitamin D Early in Life Help Prevent Alzheimer’s?

An innovative new study provides a mechanism by which getting more vitamin D

earlier in life might help prevent Alzheimer’s disease later in life.

A protein named tau is essential for the health of nerve cells. But if tau molecules

begin to bunch up into neurofibrillary tangles, they begin to damage the very cells

they were meant to keep healthy. Tau tangles are an important marker of

cognitive impairment: the more neurofibrillary tangles inside the brain cells, the

worse the cognitive impairment.

Several studies have shown that low levels of vitamin D are associated with an

increased risk of cognitive impairment and dementia.

A just published study set out to explore the possibility that more vitamin D early

in life might prevent tau tangles later in life. If that possibility proved true, that

would give rise to the possibility that getting more vitamin D might help prevent

Alzheimer’s disease.

The study included 729 people with an average age of 39 who did not have

dementia at the beginning of the study. At the beginning of the study, they had

their vitamin D levels measured. 16 years later, they had PET scans. Higher

levels of vitamin D were associated with significantly lower tau depositions in the

brain. This result was found both for the brain in general and in the regions of the

brain that are the earliest affected in Alzheimer’s.

What’s especially exciting about this study is not just the discovery of a possible

mechanism by which vitamin D might help prevent Alzheimer’s, but the

demonstration that vitamin D could significantly improve markers of dementia in

early midlife when there is a greater chance of reducing the risk of Alzheimer’s.

Neurology Journals. April 1, 2026;2 (2) e000057.