Findings support the need for clinical trials to determine if Vitamin D supplementation in younger adults could delay or help prevent the onset of dementia
Having higher levels of vitamin D in middle age may reduce the risk of dementia in later life, new Irish research suggests.
An international study led by University of Galway found that people with an abundance of the ‘sunshine vitamin’ were associated with lower levels of tau protein in the brain years later.
Presence of the protein is a biomarker for Alzheimer’s disease. However, more research is needed to prove any cause-and-effect between vitamin D and the form of dementia.
The study was led by Prof Emer McGrath and Dr Martin Mulligan from the College of Medicine, Nursing and Health Sciences at University of Galway. It was carried out in collaboration with Boston University, the Framingham Heart Study and University of Texas San Antonia.
“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,” said Prof McGrath, who is also a consultant neurologist in Galway University Hospital.
“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,” she added.
“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.”
The study involved nearly 800 people with an average age of 39 who did not have dementia.
All participants 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 that measured levels of tau and amyloid beta proteins in the brain, which are both biomarkers for Alzheimer’s disease.
A high level of vitamin D was defined as greater than 30 nanograms per milliliter and a low level was less than that number.
One-in-three participants (34 per cent) had low levels of vitamin D and one-in-20 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.
“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,” said Dr Mulligan, who was lead author on the study.
“These results suggest that higher vitamin D levels in midlife may offer protection against developing these tau deposits in the brain and that low vitamin D levels could potentially be a risk factor that could be modified and treated to reduce the risk of dementia. However, these results need to be further tested with additional studies.”
Read the study: Association of Circulating Vitamin D in Midlife With Increased Tau-PET Burden in Dementia-Free Adults – Neurology Open Access.
