Why is Vitamin D deficiency so common?

Vitamin D deficiency is widespread due to factors like reduced sun exposure (sunscreen, skin pigmentation, northern latitudes), aging, and increased body fat which sequesters Vitamin D. Up to 70% of Americans are considered deficient or insufficient.

How does Vitamin D work in the brain?

Vitamin D acts as a steroid hormone that regulates genes, enhances amyloid beta removal, modulates neuroinflammation by affecting microglia and astrocytes, upregulates neurotrophic factors for learning and memory, and decreases oxidative stress.

What are the recommended Vitamin D levels?

It's recommended to have your 25 hydroxy Vitamin D levels between 30 to 60 nanograms per milliliter. Levels above 80 ng/mL are considered too high.

How much Vitamin D should I take daily?

Most people can reach sufficient Vitamin D levels by taking 2,000 to 4,000 IUs per day, depending on their current blood levels.

Does Vitamin D help if I already have mild cognitive impairment or have the APOE E4 gene?

Yes, Vitamin D supplementation still offers benefits. For those with mild cognitive impairment, it slowed the transition to dementia, and for APOE E4 carriers, it reduced dementia incidence, though the effect was less pronounced than in healthy individuals without these risk factors.

What are the best forms of Vitamin D to take?

The video suggests that various forms, including Calcium Vitamin D, Vitamin D3, Vitamin D2, and combined forms, were all associated with lower dementia risk, with Vitamin D2 and combined forms showing a 50% reduction.

This Supplement Could Cut Your Dementia Risk By 40%

FoundMyFitness

Science & Technology5 min read18 min video

May 19, 2025|98,997 views|4,657|313

vitamin d vitamin dementia alzheimer's disease brain health brain aging supplement

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Key Moments

TL;DR

Vitamin D supplementation shows a 40% lower risk of dementia, impacting cognition and brain health.

Key Insights

A recent study indicates Vitamin D supplementation is linked to a 40% reduced risk of dementia over a decade.

Vitamin D acts as a steroid hormone regulating a significant portion of the human genome, impacting numerous bodily functions, including brain health.

Widespread deficiency/insufficiency of Vitamin D is prevalent (up to 70% of Americans), influenced by factors like sun exposure, skin pigmentation, age, and body fat.

Genetically low Vitamin D levels, determined through Mendelian randomization, also correlate with an increased dementia risk.

Vitamin D supplementation has demonstrated positive effects on cognition in individuals with mild cognitive impairment and Alzheimer's disease, improving memory, attention, and IQ.

While Vitamin D offers benefits across various groups, women and individuals with normal baseline cognitive function experienced a more significant reduction in dementia incidence.

Vitamin D supports brain health by enhancing amyloid-beta removal, modulating neuroinflammation, upregulating neurotrophic factors, and decreasing oxidative stress.

VITAMIN D SUPPLEMENTATION AND DEMENTIA RISK REDUCTION

A significant new study reveals that Vitamin D supplementation is associated with a remarkable 40% lower risk of dementia over a ten-year period. This finding is supported by five-year data showing 84% of Vitamin D supplement users remained dementia-free compared to 68% of non-users. The study, involving over 12,000 participants, also found that Vitamin D reduced dementia risk by approximately 33% in adults with mild cognitive impairment and the APOE E4 genetic risk factor, highlighting its potential neuroprotective role across different cognitive and genetic profiles.

THE ROLE OF VITAMIN D AS A STEROID HORMONE

Vitamin D transcends its classification as a mere vitamin; it functions as a potent steroid hormone that regulates nearly 5% of the human genome. Upon entering the cell nucleus, it influences the activation or suppression of genes. This fundamental biological role underscores its broad impact on health. The widespread prevalence of Vitamin D deficiency or insufficiency, affecting up to 70% of Americans, is therefore of significant concern for overall well-being and cognitive health.

PREVALENCE AND CAUSES OF VITAMIN D DEFICIENCY

Deficiency is defined as 25-hydroxy Vitamin D levels below 20 ng/mL, while insufficiency ranges from 20-30 ng/mL. Several factors contribute to this widespread issue. The body synthesizes Vitamin D through skin exposure to UVB radiation, which is blocked by sunscreen and darker skin pigmentation. Aging reduces the skin's efficiency in producing Vitamin D, and geographical location, particularly northern latitudes, can limit UVB availability for much of the year. Additionally, Vitamin D is fat-soluble and stored in body fat, making it less bioavailable with higher body fat percentages.

EVIDENCE SUPPORTING THE LINK BETWEEN VITAMIN D AND BRAIN HEALTH

Beyond observational studies, Mendelian randomization using genetic variations in Vitamin D metabolism confirms that genetically low Vitamin D levels increase dementia risk by up to 54%. Furthermore, studies using fMRI have shown that Vitamin D deficiency accelerates brain aging, evidenced by increased white matter hyperintensities, a marker of brain damage. For every 10 nmol/L increase in Vitamin D, a slight decrease in these hyperintensities was observed, suggesting a protective effect against white matter damage crucial for cognitive function.

COGNITIVE BENEFITS OF VITAMIN D SUPPLEMENTATION

While data on cognitive improvements in healthy adults is mixed, trials involving individuals with mild cognitive impairment (MCI) and Alzheimer's disease have shown promising results. Daily supplementation with 800 IUs of Vitamin D for a year led to significant improvements in memory, attention, and overall IQ in MCI patients. Similarly, Alzheimer's patients taking the same dose experienced enhanced performance on memory and attention tests, along with a reduction in blood biomarkers like amyloid-beta 42, which is associated with disease progression.

STUDY FINDINGS ON DEMENTIA RISK AND SPECIFIC POPULATIONS

The recent study on 12,388 adults found continued Vitamin D supplementation associated with a 40% lower dementia incidence and greater 5-year dementia-free survival. Benefits were observed across all groups, but women experienced a greater reduction in dementia incidence (nearly 50% lower) compared to men (26% lower), potentially linked to higher dementia prevalence in women. Individuals with normal baseline cognitive function saw a 56% lower incidence, while those with MCI had a 33% lower incidence, indicating Vitamin D is more effective in preventing than reversing existing cognitive decline.

IMPACT OF GENETIC FACTORS AND COGNITIVE IMPAIRMENT

The APOE E4 allele, a major genetic risk factor for Alzheimer's, increases dementia risk twofold with one copy and tenfold with two. Vitamin D supplementation reduced dementia incidence by 33% in APOE E4 carriers and 47% in non-carriers. However, supplementation did not fully offset the heightened risk associated with carrying APOE E4. Similarly, mild cognitive impairment significantly elevated dementia risk (nearly 400% increase with supplementation, over 600% increase without), underscoring that while Vitamin D is beneficial, it cannot entirely counteract the impact of substantial cognitive impairment or genetic predisposition.

EFFECTIVENESS OF DIFFERENT VITAMIN D FORMS AND DOSING

The study indicated that various forms of Vitamin D supplementation were associated with reduced dementia risk, including calcium-Vitamin D (44% lower risk), Vitamin D3 (37% lower risk), and Vitamin D2 (50% lower risk). Combined forms also showed a 50% lower risk. The recommended approach is to maintain 25-hydroxy Vitamin D levels between 30-60 ng/mL, avoiding levels above 80 ng/mL. Daily supplementation of 2,000-4,000 IUs is often sufficient to achieve these levels. Regular annual testing is advised to ensure optimal intake.

MECHANISMS OF VITAMIN D'S NEUROPROTECTIVE EFFECTS

Vitamin D supports brain health through multiple mechanisms. It aids in the clearance of amyloid-beta, a protein linked to Alzheimer's, by promoting its removal from the brain. As an immune modulator, Vitamin D receptors on brain cells help reduce neuroinflammation by lowering pro-inflammatory cytokine responses, which play a key role in dementia pathogenesis. It also upregulates neurotrophic factors like nerve growth factor and brain-derived neurotrophic factor, supporting neurotransmission, learning, and memory. Finally, Vitamin D decreases oxidative stress, further protecting brain cells and preventing inflammatory processes.

Mentioned in This Episode

●Supplements

●Studies Cited

●Concepts

Vitamin D for Brain Health: Key Takeaways

Practical takeaways from this episode

Do This

Consider supplementing with Vitamin D to maintain adequate levels (aim for 2,000-4,000 IUs daily).

Get a blood test to measure your 25 hydroxy Vitamin D levels and aim for 30-60 ng/mL.

Perform annual Vitamin D blood tests to ensure optimal levels.

Ensure sufficient Vitamin D intake, especially if you have high body fat, live in northern latitudes, have darker skin, or are older.

Supplementation can support brain health by enhancing amyloid beta removal, modulating neuroinflammation, and supporting neurotrophic factors.

Avoid This

Do not let Vitamin D levels go above 80 ng/mL.

Be aware that sunscreen and melanin can block UVB radiation needed for skin Vitamin D production.

Understand that as you age, your body becomes less efficient at producing Vitamin D from sun exposure.

Vitamin D Deficiency and Insufficiency in the US Population

Data extracted from this episode

Category	Percentage of Population	Average 25-hydroxy Vitamin D Level
Deficient	Approx. 30%	< 20 ng/mL
Insufficient	Approx. 40%	20-30 ng/mL
Sufficient/Optimal	Approx. 30%	> 30 ng/mL

Dementia Risk Reduction with Vitamin D Supplementation

Data extracted from this episode

Group	Supplementation Effect on Dementia Risk
Overall Study Population	40% lower risk
Adults with Mild Cognitive Impairment (MCI)	33% lower risk
Adults with MCI and APOE E4	33% lower risk
Normal Baseline Cognitive Function	56% lower risk
Non-APOE4 Carriers	47% lower risk
Women Supplementing	~50% lower incidence
Men Supplementing	26% lower incidence

Vitamin D Supplementation Efficacy by Form

Data extracted from this episode

Form of Vitamin D	Associated Lower Dementia Risk
Calcium Vitamin D	44%
Vitamin D3	37%
Vitamin D2	50%
Combined Forms	50%

Common Questions

A recent study found that Vitamin D supplementation was associated with a 40% lower risk of dementia over a decade. After 5 years, 84% of Vitamin D users remained dementia-free compared to 68% of non-users, based on a study of over 12,000 people.

Topics

Dementia Cognitive Health Supplementation MCI Neuroinflammation Amyloid Beta Vitamin D Deficiency

Mentioned in this video

studyMendelian randomization

A method using genetics to examine how environmental factors, like Vitamin D levels influenced by genes, can affect outcomes such as dementia risk.

toolsunscreen

Anything that blocks UVB radiation, including sunscreen, hinders the skin's ability to produce Vitamin D3.

studyamyloid beta

A protein linked to Alzheimer's disease pathology; Vitamin D can enhance its removal from the brain and lower plaque burden.

supplementVitamin D2

The plant-based version of Vitamin D, which was associated with a 50% lower risk of dementia when used as a supplement.

toolmicroglia

Brain immune cells where Vitamin D receptors help modulate neuroinflammation by reducing pro-inflammatory cytokine responses.

supplementcalcium Vitamin D

A form of Vitamin D supplementation that was associated with a 44% lower risk of dementia in one study.

toolastrocyte

Brain cells that, along with microglia, have Vitamin D receptors that help reduce neuroinflammation.

studyAlzheimer's disease

A neurodegenerative disease linked to APOE4 and amyloid beta pathology, where Vitamin D supplementation has shown potential benefits in reducing risk and progression.

studyAPOE E4

A key genetic risk factor for neurodegenerative diseases, which can significantly increase the risk of Alzheimer's disease if one or two alleles are present.

toolbrain-derived neurotrophic factor (BDNF)

A neurotrophic factor upregulated by Vitamin D that supports neurotransmitters, learning, and memory.

toolmelanin

The darker skin pigmentation that acts as a natural sunscreen, blunting the body's ability to make Vitamin D3 from UVB radiation.

supplementVitamin D3

A form of Vitamin D that, when used as a supplement, was associated with a 37% lower risk of dementia.

toolnerve growth factor

A neurotrophic factor upregulated by Vitamin D, which supports neurotransmitters and learning/memory.