The vitamin that works like dementia ‘repellent’

Vitamin D deficiency increases your risk of a long list of autoimmune diseases, including multiple sclerosis, rheumatoid arthritis, type 1 diabetes, inflammatory bowel disease, lupus and psoriatic arthritis.

But just how strong is the link between vitamin D deficiency and dementia?

It’s an important thing to know, since dementia is the most common neurodegenerative disorder and the most feared disease of all (even more feared than cancer and autoimmune diseases). If vitamin D can play a role in preventing dementia, that’s good information to have sooner rather than later.

And, the truth is, a lot of recent research does point to a connection between vitamin D deficiency and dementia. In fact, a recent review of the available research shows that the evidence for a vitamin D-dementia connection is getting stronger and stronger…

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What we know about vitamin D and dementia

Earlier this year, researchers from Danube University in Austria reviewed some of the available research on vitamin D and dementia. By reexamining existing studies, they determined that low vitamin D is linked to an increased risk of dementia.

Now, these researchers closely examined just six studies in their review, but their search turned up 1,870 hits in medical databases, which means there’s a lot of information floating around out there about what vitamin D can (or can’t) do for dementia. Right now, I’m going to give you a rundown of some of the most exciting findings in recent years…

A study published earlier this year found that not only was vitamin D deficiency (levels lower than 25 nmol/L) common in nursing home residents, but it was strongly associated with dementia. And two other studies published this year linked vitamin D deficiency to an increased risk of cognitive decline and a quicker rate of cognitive decline.

But one of the most dramatic vitamin D-dementia findings came from a 2014 University of Exeter study…

This study, which included 1,658 older adults, found that those with very low vitamin D levels (lower than 25 nmol/L) had 122 percent higher risk of developing dementia than those with higher levels. They also found that vitamin D deficiency of any kind (severe or moderate) was tied to a 51 percent higher risk of developing dementia.

If you’re wondering why vitamin D makes a difference in your brain health, there aren’t any hard and fast answers on that yet. But we do know that there are vitamin D receptors in your brain. That means, when your body gets vitamin D, it attaches to these receptors and impacts your thoughts, actions and ability to learn. Past research also shows that there are less vitamin D receptors in the hippocampus of people with Alzheimer’s. Since the hippocampus (which is responsible for memories and learning) is the first area that’s impacted by Alzheimer’s disease, this finding is one clue to unraveling the mystery of vitamin D and dementia.

Does all this research mean vitamin D supplementation can make a big dent in the number of people who get the disease? Well, most researchers are cautious to make that claim yet, but what we know so far looks promising.

“Even if a small number of people could benefit, this would have enormous public health implications given the devastating and costly nature of dementia,” said the author of the 2014 University of Exeter study, David J. Llewellyn, PhD, senior research fellow in clinical epidemiology.

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Preventing dementia with vitamin D

Research suggests that as you get older, your body’s ability to soak up vitamin D from the sun gets less efficient. That makes supplementing, at the right time, all the more important.

So should you take a vitamin D supplement for preventing dementia? I’d say the research is strong enough to support periodically checking your vitamin D levels and taking a supplement if they’re low.

After all, doing that will protect you from plenty of other diseases besides dementia. And the sooner you take action the better. A study that’s set for publication in early 2018 found that vitamin D deficiency in midlife (ages 55-67) is connected to cognitive decline in later life (ages 65-77).

What about people who are already in the early stages of dementia or showing signs of cognitive decline?

Once again, since science strongly supports vitamin D’s protective effect against so many diseases, staying on top of your vitamin D levels (or your loved one’s vitamin D levels) will only help your overall health. And who knows? It may help your memory and mind too.

Editor’s note: While you’re doing all the right things to protect your brain as you age, make sure you don’t make the mistake 38 million Americans do every day — by taking a drug that robs them of an essential brain nutrient! Click here to discover the truth about the Cholesterol Super-Brain!


  1. Sommer, et al. “Vitamin D deficiency as a risk factor for dementia: a systematic review and meta-analysis.” — BMC Geriatrics. 2017; 17: 16. doi: 10.1186/s12877-016-0405-0.
  2. Arnljots, et al. “Vitamin D deficiency was common among nursing home residents and associated with dementia: a cross sectional study of 545 Swedish nursing home residents.” — BMC Geriatrics. 2017 Oct 10;17(1):229. doi: 10.1186/s12877-017-0622-1.
  3. “Vitamin D and the Risk of Dementia: The Rotterdam Study.” — Journal of Alzheimer’s Disease. 2017;60(3):989-997. doi: 10.3233/JAD-170407.
  4. Feart, et al. “Associations of lower vitamin D concentrations with cognitive decline and long-term risk of dementia and Alzheimer’s disease in older adults.” — 2017 Nov;13(11):1207-1216. doi: 10.1016/j.jalz.2017.03.003.
  5. M. Goodwill, et al. “A Systematic Review and Meta-Analysis of The Effect of Low Vitamin D on Cognition.” — Journal of the American Geriatrics Society. 2017 Oct;65(10):2161-2168. doi: 10.1111/jgs.15012.
  6. Vitamin D and Dementia: A Very Close Tie — Medscape. Retrieved December 1, 2017.
  7. Alzheimer’s disease — Vitamin D Council. Retrieved December 1, 2017.
  8. M. Goodwill, et al. “Vitamin D status is associated with executive function a decade later: Data from the Women’s Healthy Ageing Project.” — Maturitas. 2018 Jan;107:56-62. doi: 10.1016/j.maturitas.2017.10.005.
Jenny Smiechowski

By Jenny Smiechowski

Jenny Smiechowski is a Chicago-based freelance writer who specializes in health, nutrition and the environment. Her work has appeared in online and print publications like Chicagoland Gardening magazine, Organic Lifestyle Magazine, BetterLife Magazine,, and