The study looked directly at levels of this vitamin in the brain, about which little is known.
Higher levels of vitamin D in the brain are linked to better cognitive function and less decline with age, a study finds.
Indeed, adequate vitamin D levels have repeatedly been linked to lower dementia risk (1, 2, 3) by research.
One study has even suggested that adequate levels of vitamin D could prevent almost one-in-five cases of dementia (Navale et al., 2022).
However, the link remains somewhat controversial, with other studies finding no connection (also: Owusu et al., 2018).
This research, though, looked directly at vitamin D levels in the brain, about which little is known.
Professor Sarah Booth, study co-author, said:
“This research reinforces the importance of studying how food and nutrients create resilience to protect the aging brain against diseases such as Alzheimer’s disease and other related dementias.”
Vitamin D markers
The study, which tracked the cognitive health of 290 seniors, analysed their brain tissue for vitamin D after they died.
Dr Kyla Shea, the study’s first author, said:
“Many studies have implicated dietary or nutritional factors in cognitive performance or function in older adults, including many studies of vitamin D, but all of them are based on either dietary intakes or blood measures of vitamin D.
We wanted to know if vitamin D is even present in the brain, and if it is, how those concentrations are linked to cognitive decline.”
The researchers found that people with higher levels of vitamin D in their brains had better cognitive function.
However, they found no link between vitamin D markers and other physiological signs of Alzheimer’s.
This means it is difficult to pinpoint the mechanism by which vitamin D might be beneficial.
Dr Shea said:
“Dementia is multifactorial, and lots of the pathological mechanisms underlying it have not been well characterized.
Vitamin D could be related to outcomes that we didn’t look at yet, but plan to study in the future.”
How much vitamin D?
Despite these findings, it is not recommended to take high levels of vitamin D as a preventative measure.
Recommended doses are 600 IU per day for people under 70 and 800 IU for those over 70.
Dr Shea said:
“We now know that vitamin D is present in reasonable amounts in human brains, and it seems to be correlated with less decline in cognitive function.
But we need to do more research to identify the neuropathology that vitamin D is linked to in the brain before we start designing future interventions.”
The study was published in the journal Alzheimer’s & Dementia (Shea et al., 2022).
