Vitamin D and Brain Health

Vitamin D is a fat-soluble vitamin involved in numerous physiological processes in the body. It is found in several foods like salmon and other oily fish, fortified in items like orange juice and milk and available as a supplement. It is produced naturally when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis from cholesterol. 

Low vitamin D levels have been linked to fatigue, osteopenia/osteoporosis, muscle weakness, mood changes and increased frequency of illness. It’s role in cognitive health is of particular interest as low vitamin D levels have been linked to an increased risk of dementia and Alzheimer’s disease. 

Studies have shown vitamin D may play several roles in supporting brain health:

Neuroprotection

Vitamin D receptors are found all throughout the brain, but highly concentrated in areas involved in memory and executive function like the hippocampus and cortex. 

Vitamin D protects the brain cells in these areas by supporting neuron growth and regulating calcium levels to prevent toxicity.

Vitamin D has also been shown to reduce inflammation and oxidative stress which can damage neurons.

Vascular Health

Impaired cerebral blood flow can impact the supply of oxygen and nutrients delivered to the brain. Poor vascular health is risk factor for cognitive decline and vascular dementia. 

Vitamin D supports the endothelial lining of blood vessels which can lower stroke and microinfarct risk. 

Amyloid Clearance

The buildup of beta-amyloid plaques in the brain is a hallmark of Alzheimer’s disease. Some studies have shown that vitamin D may help reduce the accumulation of beta-amyloid and support the macrophage activity involved in clearing plaques.

Low vitamin D levels are consistently associated with a higher risk of cognitive decline and dementia, and studies show that optimizing low vitamin D levels may help slow decline or improve cognition in people who are deficient. 

In those with suboptimal vitamin D levels, every 4 ng/mL increase lowered the risk of dementia by 1.2%.  An adequate level of vitamin D is considered 30-50 ng/mL with the functional optimal range being 50-90 ng/mL.

Vitamin D is a modifiable risk factor and not a singular cure. Optimizing levels should be done in conjunction with other brain health supporting strategies such as exercise, stress management and proper nutrition.

Source:

https://pubmed.ncbi.nlm.nih.gov/28758188/

https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1649841