Vitamin D and brain health: does your level matter?
Quick answer
Vitamin D plays roles in nerve function and sleep-wake regulation. A small preliminary Emory University study found that adults with mild cognitive impairment and sleep disturbance who took 5,000 IU (international units) or more daily scored over 13% higher on cognitive tests than those taking none. The study cannot show that vitamin D prevents dementia, and at CogMission we say the key message is to know your level.
Vitamin D is one of those nutrients I keep coming back to when we talk about brain health. And new research gives us another reason to pay attention to it.
A recent study from Emory University looked at adults with both mild cognitive impairment and sleep disturbance , a group already considered at increased risk of dementia. Interestingly, those taking 5,000 IU or more of vitamin D daily scored more than 13% higher on cognitive testing than those taking none.
It’s a small preliminary study, so we certainly can’t conclude that 5,000 IU of vitamin D prevents dementia. But I find the findings particularly interesting because they reflect something we see clinically.
At CogMission, we don’t prescribe a blanket dose of vitamin D. We test, supplement and retest, adjusting the dose according to the individual’s blood levels. There is a reference range, but our aim is to help people reach an optimal level rather than simply avoiding deficiency.
In practice, I find that many people need somewhere around 4,000–5,000 IU daily to reach and maintain the levels we are looking for — although some need considerably less and others more. That’s precisely why testing matters.
Vitamin D also sits at an interesting crossroads between brain health and sleep. It plays roles in nerve function and sleep-wake regulation, while poor sleep itself is increasingly recognised as an important modifiable risk factor for cognitive decline.
For me, the message isn’t simply “take more vitamin D.”
It’s know your level.
When we’re thinking about protecting the brain for decades to come, getting the fundamentals right matters — and vitamin D may be one of those fundamentals.
Common questions
How much vitamin D do I need for brain health?
There is no single dose. At CogMission, we do not prescribe vitamin D as a blanket dose. We test levels, supplement and retest, adjusting the dose to blood results. In our experience, many people need around 4,000–5,000 IU daily, though some need considerably less and others more.
Can vitamin D prevent dementia?
We cannot conclude that vitamin D prevents dementia. A small preliminary Emory University study found that adults with mild cognitive impairment and sleep disturbance who took 5,000 IU or more daily scored over 13% higher on cognitive testing than those taking none, but this does not show prevention.
Is vitamin D linked to sleep and memory?
Vitamin D plays roles in nerve function and sleep-wake regulation. Poor sleep is also increasingly recognised as an important modifiable risk factor for cognitive decline, which is why vitamin D sits at an interesting crossroads between brain health and sleep.
This article is for general information and isn’t a substitute for personal medical advice. Please speak to your GP (family doctor) or a qualified practitioner before making changes to medication or treatment.