Vitamin D in Midlife Linked to Brain Health Later in Life
New research suggests vitamin D may support brain health and may be linked to dementia-related brain changes later in life.
A study published on April 1, 2026, in Neurology® found that people who had higher vitamin D levels in midlife were more likely to have lower levels of tau protein in their brains years later. Tau is one of the key proteins linked to Alzheimer’s disease and other forms of dementia. When tau builds up abnormally in the brain, it can damage brain cells and interfere with memory and thinking.
The researchers followed nearly 800 adults who did not have dementia at the start of the study. Participants were about 39 years old on average when their blood vitamin D levels were first measured. More than a decade later, they had brain scans to look for signs of Alzheimer ’s-related proteins, including tau and amyloid beta.
The results showed that people who had higher vitamin D levels earlier in life had lower amounts of tau protein in their brain years later. However, vitamin D levels were not linked to amyloid beta levels.
“These results suggest that higher vitamin D levels in midlife may offer protection against developing these tau deposits in the brain,” said study author Martin David Mulligan, MB BCh BAO. “Midlife is a time where risk factor modification can have a greater impact.”
About one-third of participants had low vitamin D levels, and only 5 percent were taking vitamin D supplements.
This study does not prove that vitamin D prevents dementia or directly lowers tau protein levels. One limitation is that vitamin D levels were measured only once during this study.
Vitamin D levels can often be improved through safe sun exposure, diet, or supplements, under a doctor’s guidance. The researchers say more studies are needed to confirm whether boosting vitamin D could play a role in protecting brain health.
Key Takeaways
- In this study, higher vitamin D levels in midlife were linked to lower levels of tau protein years later.
- Vitamin D levels were not linked to amyloid beta levels.
- This study does not prove that vitamin D prevents dementia or directly lowers tau protein levels.
This article was medically reviewed by Sarah Song, MD, MPH, FAAN.
