In the UK, vitamin D deficiency affects 23% of adults (21% in those over 65yo), in winter the prevalence even rises to 40% (29% in those over 65yo). Vitamin D is mainly known for its role in the regulation of calcium homeostasis and in bone integrity, but it also plays an important role in the brain and is even considered neuroprotective.
Vitamin D promotes amyloid metabolism and clearance, neuronal and synaptic growth and neurotransmission. Many studies show the association between low vitamin D status and cognitive impairment associated with ageing (dementia). More recently, a study looked at vitamin D in 4 areas of the brain, 2 associated with Alzheimer, 1 with dementia and 1 with no association to cognitive decline. They found that high concentration of vitamin D in the 4 areas were correlated with better cognitive function. In another study, MR analyses suggested a causal effect of vitamin D deficiency on dementia.
The exact mechanisms by which vitamin D acts on cerebral health are not yet elucidated, but one thing is certain: whether it is for your bones or brain, take your daily 10 microgram vitamin D supplement between October and March.