Galway study finds Vitamin D may help to reduce the risk of dementia
Higher levels of vitamin D in middle age may protect against dementia years later, according to a new international study led by University of Galway. That determined that higher levels of vitamin D in middle age is associated with lower levels of tau protein in the brain – and that protein is a sign of dementia in later life.
But researchers also point out that the study does not prove cause and effect; it only shows an association – and the results need to be confirmed with additional studies.
The findings were published in Neurology Open Access, an official journal of the American Academy of Neurology, last week.
It found that higher vitamin D levels are associated with lower levels of the Alzheimer’s biomarker, tau protein in the brain, years later.
The study was led by Professor Emer McGrath and Dr Martin Mulligan, from the College of Medicine, Nursing and Health Sciences at University of Galway and Galway University Hospital.
The study involved nearly 800 people with an average age of 39 who did not have dementia. It was carried out in collaboration with Boston University, the Framingham Heart Study and University of Texas San Antonia.
Professor Emer McGrath, Associate Professor in Medicine, University of Galway and Consultant Neurologist, Galway University Hospital, was the senior author of the report.
“This study demonstrates an association between higher vitamin D in mid-life and a lower burden of abnormal tau protein in the brain, a marker of Alzheimer’s disease,” she said.
“Vitamin D in mid-life could be an important factor to protect future brain health. While previous research has linked low vitamin D in adults over 70 with an increased risk of dementia, this study is among the first to look at younger adults at mid-life, around the average age of 39.
Low vitamin D in mid-life may be an important target to reduce the risk of early signs of preclinical dementia in the brain
“Low vitamin D in mid-life may be an important target to reduce the risk of early signs of preclinical dementia in the brain.
“However, while these findings are very interesting, they only demonstrate an association between vitamin D and early signs of dementia in the brain. Further studies, for example a clinical trial, will be required to determine if vitamin D supplements could prevent dementia," she added.
Lead author, Dr Martin Mulligan, PhD researcher at University of Galway, explained the findings of the study.
“We found that higher vitamin D levels were associated with lower tau deposition in regions of the brain that are known to be affected earliest in Alzheimer's disease,” he said.
All participants in the study had the level of vitamin D in their blood measured at the start of the study.
They had brain scans an average of 16 years later to measure levels of tau and amyloid beta proteins in the brain, both biomarkers for Alzheimer’s disease.
A high level of vitamin D was defined as greater than 30 nanograms per milliliter (ng/mL) and a low level was less than that number.
A total of 34% of participants had low levels of vitamin D and 5% were taking vitamin D supplements. The results took into account other factors that could affect tau levels, such as age, sex and symptoms of depression.
The results showed that higher vitamin D levels are associated with lower levels of the Alzheimer’s biomarker tau protein years later.