Higher levels of vitamin D in middle age could protect against dementia in later life, an international study led by University of Galway suggests.
The research, published on Thursday in Neurology Open Access, an official journal of the American Academy of Neurology, found an association between having higher levels of vitamin D in middle age and lower levels of tau protein in the brain – a sign of dementia – years later.
The researchers cautioned that the findings do not prove cause and effect, and that additional studies are required, but described the results as “promising”.
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.
The participants then had brain scans about 16 years later that measured biomarkers for Alzheimer’s disease.
A total of 34 per cent of participants had low levels of vitamin D and 5 per cent 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.
Prof Emer McGrath, senior author and consultant neurologist at Galway University Hospital, said vitamin D 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 midlife, around the average age of 39. Low vitamin D in midlife may be an important target to reduce the risk of early signs of preclinical dementia in the brain,” she said.
“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.”
