Life Extension Magazine®

Scan showing benefits of vitamin d in the brain

How Vitamin D Protects Brain Function

Low levels of vitamin D are associated with memory loss and increased dementia risk. In a new discovery, researchers show that certain brain cells contain receptor sites for vitamin D.

Scientifically reviewed by: Dr. Amanda Martin, DC, in May 2022. Written by: Robert Hathaway.

Vitamin D is demonstrating some impressive brain-protecting roles.

These include supporting growth of new brain cells and encouraging removal of amyloid before it leads to Alzheimer’s.1-3

Low levels of vitamin D are associated with memory loss and increased risk for dementia.3-10

According to mainstream medical standards, 64% of Americans don’t have enough vitamin D to keep tissues functioning at peak capacity.11

Life Extension® long ago suggested that people supplement with 5,000-8,000 IU daily in order to achieve optimal levels of vitamin D.

Combatting vitamin D deficiency isn’t difficult. Low-cost vitamin D supplements are readily available.

Why Is Vitamin D Important for Brain Health?

Why Is Vitamin D Important for Brain Health?  

Researchers have discovered certain cells in the brain have receptors for vitamin D that keep the brain healthy and functioning.2,12,13

In animal models of Alzheimer’s disease, activated vitamin D helped clear the brain of amyloid, the toxic protein that can build up and contribute to Alzheimer’s pathology.14,15

In a mouse model of Alzheimer’s disease, vitamin D was shown to support neurogenesis,1 or the formation of new healthy brain cells, which occurs during brain development and may occur in some parts of the brain later in life.

Vitamin D protects against neuro-inflammation and neurodegenerative disorders in animals.16,17

Human studies show that higher vitamin D levels are associated with reduced disability and cognitive impairment following stroke.13

What You Need to Know
Vitamin D and Brain Function

Vitamin D and Brain Function

  • Vitamin D deficiency is very common and significantly impacts brain health.
  • Mild cognitive impairment and dementia are common forms of age-related cognitive decline.
  • Both disorders and other aspects of healthy brain function have been consistently associated with levels of vitamin D in the blood.
  • Higher levels of vitamin D appear protective, and lower levels significantly increase the risk for future cognitive dysfunction.
  • Supplementation and regular testing can be helpful in maintaining healthy levels of vitamin D in the body.

Vitamin D and Age-Related Cognitive Decline

Vitamin D and Age-Related Cognitive Decline
Supplementation and
regular testing can be
helpful in maintaining
healthy levels of
vitamin D in the body.

The differences in loss of cognitive function in people in the same age group are striking, with some experiencing a rapid decline.

Depending on the severity and quickness of the loss, the decline can be diagnosed as either mild cognitive impairment or dementia.

Mild cognitive impairment appears as a decline in memory function and other mental processing skills. This condition is very common, affecting roughly 15%-20% of all individuals 65 years of age and older.18 People with mild cognitive impairment are at high risk for dementia.

Dementia is a contributor to death in the elderly, and Alzheimer’s disease is the most common cause of dementia.

Approximately 10% of those 65 years and older live with Alzheimer’s disease. Over 5 million people in the US suffer from Alzheimer’s, and this number is expected to rise in the years to come.19

What does this have to do with vitamin D? Low vitamin D levels have been associated with deteriorating brain function, and vitamin D levels have consistently been found to be predictive of risk for mild cognitive impairment and dementia.8,9 In fact, the risk of developing dementia is greater in those with vitamin D deficiency.20

One study found that a person’s vitamin D level could predict cognitive problems 13 years later. Those with higher vitamin D levels had less cognitive impairment with better short-term and working memory.21

Several other studies found this same link between lower vitamin D levels and the risk for cognitive impairment.7,22-24 In one of these studies, the risk was more than three times greater for those with the lowest levels of vitamin D.23

Vitamin D levels also appear to be associated with the structure of the brain. Normal age-related decline in brain function is associated with atrophy,25,26 the loss of volume of brain tissue over time.

In one recent study, researchers found that higher vitamin D levels were associated with more beneficial gray matter in older adults.27 Gray matter is the brain tissue where nerve cell bodies reside and form functional connections with other cells. This includes the cerebral cortex, which is the major region of the brain that controls cognition, including executive function, new memory formation, and memory recall.

Life Extension Recommendations

There are no universal guidelines for frequency of vitamin D testing. However, given the high prevalence of vitamin D deficiency and the strong association of low vitamin D levels with several health issues, annual testing and supplementation to achieve adequate blood levels is highly recommended.

Annual blood tests can enable one to know whether they are taking the correct dosage to ensure optimal blood levels of vitamin D.

If you do not already maintain an optimal blood level of 25-hydroxyvitamin D of 50 to 80 ng/mL, then take around 5,000 to 8,000 IU of vitamin D daily with a meal for better absorption.


Deficiency of vitamin D is a common problem.  

Deficiency of vitamin D is a common problem.

In addition to affecting other systems in the body receptors for vitamin D are found throughout the brain, tightly linking nervous system function to vitamin D levels.

Vitamin D appears to support brain function and protect against neurodegeneration.

Various cognitive impairments, ranging from mild memory loss to Alzheimer’s dementia, have been associated with lower levels of vitamin D.

Life Extension’s recommended dose range is 5,000 to 8,000 IU of vitamin D3 daily. Heavier people often need the higher doses and absorption is much better when the vitamin is taken with a meal that contains fat.

Annual blood tests can enable one to know whether they are taking the correct dosage to ensure optimal blood levels of vitamin D.

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.


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  2. Groves NJ, McGrath JJ, Burne TH. Vitamin D as a neurosteroid affecting the developing and adult brain. Annu Rev Nutr. 2014;34:117-41.
  3. Annweiler C, Beauchet O. Vitamin D-mentia: randomized clinical trials should be the next step. Neuroepidemiology. 2011;37(3-4):249-58.
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  11. Mitchell DM, Henao MP, Finkelstein JS, et al. Prevalence and predictors of vitamin D deficiency in healthy adults. Endocr Pract. 2012 Nov-Dec;18(6):914-23.
  12. Harms LR, Burne TH, Eyles DW, et al. Vitamin D and the brain. Best Pract Res Clin Endocrinol Metab. 2011 Aug;25(4):657-69.
  13. Yalbuzdag SA, Sarifakioglu B, Afsar SI, et al. Is 25(OH)D Associated with Cognitive Impairment and Functional Improvement in Stroke? A Retrospective Clinical Study. J Stroke Cerebrovasc Dis. 2015 Jul;24(7):1479-86.
  14. Durk MR, Han K, Chow EC, et al. 1alpha,25-Dihydroxyvitamin D3 reduces cerebral amyloid-beta accumulation and improves cognition in mouse models of Alzheimer’s disease. J Neurosci.2014 May 21;34(21):7091-101.
  15. Ito S, Ohtsuki S, Nezu Y, et al. 1alpha,25-Dihydroxyvitamin D3 enhances cerebral clearance of human amyloid-beta peptide(1-40) from mouse brain across the blood-brain barrier. Fluids Barriers CNS. 2011 Jul 8;8:20.
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  19. Available at: Accessed September 5, 2018.
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  27. Brouwer-Brolsma EM, van der Zwaluw NL, van Wijngaarden JP, et al. Higher Serum 25-Hydroxyvitamin D and Lower Plasma Glucose Are Associated with Larger Gray Matter Volume but Not with White Matter or Total Brain Volume in Dutch Community-Dwelling Older Adults. J Nutr. 2015 Aug;145(8):1817-23.