The Link Between Vitamin D and Alzheimer’s Disease

Several months ago, I wrote about the connection between Alzheimer’s disease and inflammation, and how one of the most important things you can do to reduce your risk is to better control inflammation.

In that article, I wrote about several nutrients that can lower inflammation in the brain, including omega-3 fatty acids. According to one report, omega-3s have a “protective role in mild cognitive impairment, dementia, and the risk and progression of Alzheimer’s disease…”1

But dementias like Alzheimer’s are extremely complex. The more we learn, the clearer it becomes that several factors on top of inflammation can play a role in their development. For example, studies are now starting to show the significance of vitamin D on brain health and disease.

Protection Against Plaques

The brain contains multiple vitamin D receptors. These receptors receive signals that direct cells do something or act a certain way.

Researchers are still learning all the ways these receptors influence the brain. But studies show that one critical job they have is to protect against things that can cause damage, including plaques and tangles—two hallmark signs of Alzheimer’s disease.

Plaques, caused by the buildup of a sticky protein called amyloid beta, disrupt or block cellular communication in the brain. Another protein, tau, leads to the formation of tangles. An overabundance of tau collapses the usually straight highways where nutrients travel throughout the brain. When these highways become twisted and tangled, they can no longer carry essential components to brain cells, causing them to die.

One report found that the biologically active form of vitamin D (D3) has “neuroprotective effects, including the clearance of amyloid plaques.”2

Prevention of Dementias

Research has also established a link between vitamin D and risk of Alzheimer’s and other dementias.

On one hand, higher amounts of vitamin D in the body have been shown to decrease risk. In one study that followed 489 women for seven years, scientists concluded that, “higher vitamin D dietary intake was associated with a lower risk of developing Alzheimer’s disease…”3

At the same time, deficiencies in this nutrient have been associated with increased risk.

A long-term study out of Denmark followed more than 10,000 people for 30 years. A total of 418 ended up with Alzheimer’s, and another 92 developed vascular dementia. The affected patients had significantly lower vitamin D compared to the other participants.4

Similar conclusions were found in another study that followed 1,658 people. After five years, 171 people developed dementia, including 102 cases of Alzheimer’s disease. Risk increased dramatically in the patients whose D levels fell below 50 nmol/L.5 (Most medical societies and organizations recognize a reading of 50 nmol/L, or 20 ng/ml, as insufficient or deficient.)

And a report published in the prestigious JAMA concluded, “Low vitamin D status was associated with accelerated decline in cognitive function domains in ethnically diverse older adults…”6

Getting Your Daily Dose of D

Based on the latest research, I believe the link between vitamin D and Alzheimer’s is one that should not be ignored. This is especially important considering an estimated 1 billion people worldwide are deficient in this nutrient.

Many doctors check vitamin D status with routine blood tests, so you can easily find out if you have a deficiency or not. According to the Vitamin D Council, adequate levels range from 40-80 ng/ml, and adults should take about 5,000 IU per day to reach and maintain that level. If you take a supplement, be sure to choose D3, the form your body can absorb and use most efficiently.

Of course, the cheapest and most reliable way to get your daily dose of D is through sunlight. Vitamin D is known as “the sunshine vitamin” because your body produces it in response to exposure to ultraviolet radiation from the sun.

Going outside for 10-20 minutes in the midday sun without sunscreen can create up to 10,000 IU of vitamin D! (Lighter skinned people need less time; darker-skinned individuals may need up to 20 minutes.) You can’t “overdose” on vitamin D that’s synthesized through sun exposure because your body produces only the amount that it needs. (It’s truly an amazing machine.)

With the warmer summer weather upon us, I encourage you to get outside every day and bask in the glorious sunshine for 10-20 minutes. Go for a walk or jog, or sit down with a glass of iced tea and admire your surroundings. Just enjoy those precious, peaceful few minutes, knowing that you’re very likely doing your brain, body, and spirit a lot of good. (After those 10-20 minutes, be sure to apply sunscreen so that you don’t get burned…)


  1. Waitzberg DL and Garla P. Nutr Hosp. 2014 Sep 1;30(3):467-77.
  2. Soni M, et al. Scand J Clin Lab Invest Suppl. 2012;243:79-82.
  3. Annweiler C, et al. J Gerontol A Biol Sci Med Sci. 2012 Nov;67(11):1205-11.
  4. Afzal S, et al. Alzheimers Dement. 2014 May;10(3):296-302.
  5. Littlejohns TJ, et al. Neurology. 2014 Sep 2;83(10):920-8.
  6. Miller JW, et al. JAMA Neurol. 2015 Nov;72(11):1295-303.

About Author

Brian Matthews

Brian Matthews is the President of Gene Smart and the leader of our Gene Smart team. His mission is to provide supplements to help you control your inflammation, your weight, and your life, based on the latest scientific information.

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