Can low vitamin D levels raise dementia risk? Yes, research shows that people with low vitamin D have a higher chance of developing dementia, with studies linking deficiency to up to a 32 percent increased risk or more in severe cases.
Vitamin D is a nutrient that helps your body absorb calcium and supports brain health. When levels drop too low, it may disrupt how the brain handles calcium, which is key for forming memories. A meta-analysis in BMC Neurology found that vitamin D deficiency raises dementia risk by 32 percent overall, and severe deficiency, defined as 10 ng/ml or lower in blood tests, boosts it by nearly 50 percenthttps://www.mindbodygreen.com/articles/getting-ample-vitamin-d-reduces-your-dementia-risk-by-32-how-to-achieve-and-maintain-healthy-vitamin-d-levels. This happens because low vitamin D can mess up calcium balance in brain cells, speeding up neuron aging.
Low vitamin D also fails to protect the brain from damage. It acts like an antioxidant to fight oxidative stress and excess glutamate, a brain chemical that can kill neurons if levels get too high. A 2018 study in the Journal of Neurobiological Studies noted these protective effectshttps://www.mindbodygreen.com/articles/getting-ample-vitamin-d-reduces-your-dementia-risk-by-32-how-to-achieve-and-maintain-healthy-vitamin-d-levels. Observational studies often show even stronger links, with vitamin D deficiency tied to 80 percent higher dementia risk, and genetic studies confirming about 50 percenthttps://www.youtube.com/watch?v=ZG77-aQNMqI. People who supplement with vitamin D cut their risk by 40 percent in some trials, and cognition improved after a year of use.
About 29 percent of U.S. adults lack enough vitamin D, making this a common issue as dementia rates rise worldwidehttps://www.mindbodygreen.com/articles/getting-ample-vitamin-d-reduces-your-dementia-risk-by-32-how-to-achieve-and-maintain-healthy-vitamin-d-levels. Multiple reviews confirm higher vitamin D links to lower Alzheimer’s and dementia oddshttps://www.grassrootshealth.net/blog/vitamin-d-insights-why-observational-evidence-outperforms-clinical-trials-dr-grant-oct-2025/https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1677197/full. Getting enough through sun, food, or supplements may help, but factors like magnesium matter too, as it helps regulate vitamin D levelshttps://www.sciencedaily.com/releases/2025/12/251228020010.htm.
Sources
https://www.mindbodygreen.com/articles/getting-ample-vitamin-d-reduces-your-dementia-risk-by-32-how-to-achieve-and-maintain-healthy-vitamin-d-levels
https://pmc.ncbi.nlm.nih.gov/articles/PMC12709776/
https://www.youtube.com/watch?v=ZG77-aQNMqI
https://www.sciencedaily.com/releases/2025/12/251228020010.htm
https://www.grassrootshealth.net/blog/vitamin-d-insights-why-observational-evidence-outperforms-clinical-trials-dr-grant-oct-2025/
https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1677197/full
