A long-term study found that people with higher vitamin D levels in their 30s and 40s had lower tau levels in the brain around 16 years later.Tau is a protein closely linked to Alzheimer’s disease and other forms of dementia.The study found no link with amyloid beta and cannot prove vitamin D directly reduces dementia risk.
A new study suggests vitamin D status in mid-life may be linked to brain health years later.
Researchers followed 793 adults who were free of dementia at the start of the study.
Participants were around 39 years old on average when their vitamin D levels were measured.
About 16 years later, they had brain scans to assess tau and amyloid beta, two proteins linked to Alzheimer’s disease.
The key result was that people with higher vitamin D levels in mid-life had lower levels of tau later on.
That is potentially important because tau accumulation is strongly associated with neurodegeneration and cognitive decline.
The study did not find the same relationship with amyloid beta.
That makes the result more specific, but also more complicated.
It suggests vitamin D may be linked to some aspects of Alzheimer’s biology and not others.
As ever, there are limits.
Vitamin D was measured only once, so the study cannot tell us what happened to levels over time.
It was also observational, which means it shows a link, not proof that vitamin D itself changed the brain outcome.
Still, the study makes a fair point.
Mid-life is often when risk factors can still be modified, so it is a sensible stage to look at things like vitamin D, blood pressure and metabolic health.
The big mistake would be to oversell it.
This is not evidence that vitamin D supplements prevent dementia.
It is a useful signal that deserves further study.
