How Vitamin D Helps Your Brain

Perhaps vitamin B12 comes to mind when you think of vitamins and brain health, and for good reason. A deficiency in vitamin B12 can cause symptoms that mimic Alzheimer's disease, and sometimes those symptoms can be reversed with adequate provision of this important vitamin.

But there's another vitamin out there that's also important for your brain- vitamin D. Vitamin D is traditionally associated with bone health, but research indicates it may be necessary for a healthy brain.

Low Levels of Vitamin D Have Been Connected to a Decline in Cognition

One study measured the levels of vitamin D over eight years in 858 people older than 65 years. It then compared their scores on evaluation tools including the Trail Making Test and the Mini Mental State Exam. Based on the results, the researchers determined that people with a severe deficiency in vitamin D experienced a significant cognitive decline, compared to those with adequate vitamin D levels.

A second study reached a similar conclusion. The researchers monitored more than 6000 women over the course of four years and found that those with a significant deficiency of vitamin D were more likely to demonstrate cognitive impairment initially and more likely to decline in cognition over time.

Yet another study involving 95 participants found that people with memory loss complaints and mild cognitive impairment were more likely to have lower levels of vitamin D.

Can Vitamin D Be Used to Treat Dementia?

Several research studies are being conducted to determine if increasing vitamin D levels after dementia has already been diagnosed can improve cognition. The answer is thus far unclear.

One study found that increased levels of vitamin D had the potential for both positive and negative effects in the brain, so researchers concluded that more study was needed.

Other scientists tested the administration of vitamin D in combination with Namenda (memantine), a medication that's approved to treat Alzheimer's disease, to people with dementia. The results indicated that the combination of the medication and vitamin D improved the participants' cognitive functioning over the course of six months, while neither Namenda alone nor vitamin D alone demonstrated this improvement. 

A third study investigated the combination of vitamin D and curcumin and found that when used together, they appeared to be more effective in breaking up excess amyloid beta plaque build-up in the brains of people with Alzheimer's disease.

Consult with Your Doctor

As is the case with most substances, vitamin D does have the potential to interact with other medications and supplements, so you should always consult with your physician before changing your medical routine.


Archives of Internal Medicine. 2010 Jul 12;170(13):1135-41. Vitamin D and risk of cognitive decline in elderly persons.

Cognitive and Behavioral Neurololgy: Official Journal of the Society for Behavioral and Cognitive Neurology. 2012 Sep;25(3):121-7. Effectiveness of the combination of memantine plus vitamin D on cognition in patients with Alzheimer disease: a pre-post pilot study.

European Journal of Neurology. 2012 Jul;19(7):1023-9. Vitamin D insufficiency and mild cognitive impairment: cross-sectional association.

Journal of Alzheimer's Disease. Volume 29, Number 1 / 2012. Genomic and Nongenomic Signaling Induced by 1α,25(OH)2-Vitamin D3 Promotes the Recovery of Amyloid-β Phagocytosis by Alzheimer's Disease Macrophages.

Journal of Alzheimer's Disease. 2013;33(3):659-74. Low serum vitamin D concentrations in Alzheimer's disease: a systematic review and meta-analysis.

The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences. 2012 Oct;67(10):1092-8. Association between serum 25(OH) vitamin D and the risk of cognitive decline in older women.

University of Maryland Medical Center. Possible Interactions with: Vitamin D. May 31, 2013.

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