Scientists measured vitamin D levels in people who were about 39 years old and did not have dementia. Sixteen years later, they scanned the participants’ brains.
The scans looked for two proteins linked to Alzheimer’s disease: tau and amyloid‑beta. The researchers noticed that those who had more vitamin D early in life showed lower amounts of tau many years later.
How the Study Was Done
Nearly 800 volunteers gave a blood sample at the start of the study. The scientists recorded the amount of vitamin D in each sample. After about 16 years, the same people underwent brain imaging to see how much tau and amyloid‑beta they had.
Vitamin D levels above 30 nanograms per milliliter were called “high”; lower levels were called “low.” About one‑third of the group had low vitamin D, and only five percent took vitamin D supplements.
What the Results Show
When the data were adjusted for age, gender, and signs of depression, higher vitamin D still matched with lower tau levels. There was no similar link between vitamin D and amyloid‑beta.
Researchers said the finding is encouraging because it suggests that having enough vitamin D in middle age might help keep tau levels down later on, when the brain is more vulnerable.
Things to Keep in Mind
- The study only measured vitamin D once, not over the whole period.
- It shows a connection, not a cause‑and‑effect relationship.
- More research is needed to see if boosting vitamin D can truly lower dementia risk.
The work was funded by several health agencies, including the National Institute on Aging and the Irish Research Council.