A groundbreaking study has found that vitamin D supplementation is associated with a significant 40% reduction in dementia risk over a 10-year period, according to research discussed by Dr. Rhonda Patrick.
The large-scale study, which included over 12,000 adults, revealed that after just 5 years, 84% of vitamin D supplement users remained dementia-free compared to only 68% of non-users. The protective effect was observed across various populations, with particularly notable benefits for certain groups.
“Vitamin D is not just a vitamin,” explains Dr. Patrick. “Vitamin D gets converted into a steroid hormone that regulates over a thousand genes in our body. It enters the nucleus of our cells and it regulates, it activates and turns on or it suppresses and turns off up to nearly 5% of the protein encoding human genome.”
The findings are especially promising for those with genetic risk factors for neurodegenerative diseases. Vitamin D reduced dementia risk by approximately 33% in adults with mild cognitive impairment who also carried the APOE E4 gene variant—a key genetic risk factor that can increase Alzheimer’s risk up to tenfold in individuals with two copies.
The study’s results gain additional significance considering that up to 70% of Americans have insufficient or deficient vitamin D levels. About 30% are clinically deficient with levels below 20 nanograms per milliliter, while another 40% fall into the insufficient range between 20-30 ng/mL.
Several factors contribute to widespread vitamin D deficiency, including:
– Limited sun exposure
– Sunscreen use
– Darker skin pigmentation
– Advanced age (a 70-year-old produces four times less vitamin D from sun exposure than a 20-year-old)
– Northern latitude residence
– Higher body fat percentage
The study revealed interesting demographic differences in vitamin D’s protective effects. Women derived substantially greater benefits than men, experiencing nearly a 50% lower dementia incidence compared to non-supplementing women, while men saw a 26% reduction.
Additionally, those with normal baseline cognitive function who supplemented with vitamin D had a 56% lower dementia incidence, while those with existing mild cognitive impairment still experienced a 33% reduction.
This research builds upon multiple previous studies linking vitamin D to brain health. These include Mendelian randomization studies showing genetically low vitamin D levels increase dementia risk by up to 54%, and neuroimaging research demonstrating how vitamin D deficiency accelerates brain aging through increased white matter hyperintensities.
The study found that all forms of vitamin D supplementation provided protection: calcium with vitamin D (44% lower risk), vitamin D3 (37% lower risk), vitamin D2 (50% lower risk), and combined forms (50% lower risk).
Dr. Patrick suggests that most people can maintain optimal vitamin D levels (between 30-60 ng/mL) with daily supplements of 2,000-4,000 IU, though annual blood testing is recommended to ensure appropriate dosing.
Vitamin D appears to support brain health through multiple mechanisms, including enhanced removal of amyloid beta (linked to Alzheimer’s disease), modulation of neuroinflammation, upregulation of neurotrophic factors that support learning and memory, and reduction of oxidative stress.
Given these findings and vitamin D’s wide-ranging benefits, supplementation represents a simple, inexpensive intervention that could significantly impact dementia risk across the population.