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Vitamin D supplements prevent dementia

Vitamin D supplements prevent dementiaThe number of older people is increasing rapidly, which means more and more people suffer from different types of dementia. Vitamin D supplementation may help prevent dementia or delay its progression, according to a population study that is published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring. It is important to have optimal blood levels of the nutrient throughout life, simply because it often takes years for dementia to develop, and because vitamin D has many different functions that are relevant for brain health.

More than 50 million people worldwide suffer from some type of dementia. The rate is increasing rapidly and three times as many individuals are believed to be affected when we reach year 2050. There is currently no effective treatment that can prevent or delay dementia, so it makes perfect sense to look at the underlying cause of these diseases. Vitamin D deficiency, a problem that is believed to affect one billion people worldwide, is one of the main causes. In spite of this, vitamin D’s role is heavily debated.
Scientists from the Hotchkiss Brain Institute at University of Calgary in Canada and University of Exeter in England have looked at how vitamin D supplements affected 12,388 dementia sufferers recruited from the American US National Alzheimer’s Coordinating Center. Their mean age was 71 years, and none of the participants had dementia at study start. Thirty-seven percent of the participants took a vitamin D supplement, and it turned out their risk of developing dementia was 40 percent lower compared with the group that did not take vitamin D.
A total of 2,696 study participants developed dementia over the course of 10 years. Seventy-five percent of them did not take supplements of vitamin D. It looks as if vitamin D has a positive effect on everyone, especially if you start supplementing before the onset of cognitive decline, which may be an early stage of dementia and Alzheimer’s disease.
Vitamin D appears to have a slightly better effect on women than on men. The researchers assume that estrogen may increase the activity of vitamin D, and that women need extra vitamin D after menopause due to hormonal changes.
Vitamin D supplementation also worked significantly better on people without the APOEe4 gene that predisposes for Alzheimer’s disease. Based on these observations, the scientists conclude that vitamin D supplementation has the potential to prevent dementia.

How much vitamin D is needed to prevent dementia?

Scientists from University of South Australia have analyzed data from roughly 300,000 people, who were registered in the UK Biobank. They found that low blood levels of vitamin D were linked to reduced brain volume and an increased risk of developing dementia and stroke. They also discovered that some populations may reduce their risk of dementia by 17 percent by making sure to have blood levels of vitamin D above 50 nmol/L, which is the lower threshold value. The study is published in The American Journal of Clinical Nutrition.
Some health authorities recommend that everyone take vitamin D during the winter period, while older people and vulnerable groups are advised to take high-dosed vitamin D all year round.
The need for vitamin D varies from person to person due to factors such as genetic variations, age, skin color, and BMI. One should ideally try to have blood levels in the optimal range which is between 75 and 120 nmol/L.
High-dosed vitamin D supplements with 20-100 micrograms in each pill are available. Also remember to get plenty of magnesium, a mineral that is important for the body’s ability to activate vitamin D in the cells.

Facts about vitamin D, the brain, and cognitive functions

  • We have vitamin D receptors (VDR) in several different parts of the brain
  • Vitamin D controls different genes by means of on-off switches
  • Vitamin D regulates different neurotransmitters
  • Vitamin D is able to counteracts oxidative stress and inflammation, which can cause atherosclerosis and damage to nerve cells and other tissues
  • Vitamin D counteracts the accumulation of potentially harmful proteins (beta-amyloid and tau) in the brain


Maryam Ghahremani et al. Vitamin D supplementation and incident dementia: Effects of sex, APOE, and baseline cognitive status. Alzheimer´s & Dementia: Diagnosis, Assessment & Disease Monitoring, 2023

Shreeya S Navale et al. Vitamin D and brain health: an observational and Mendelian randomization study. The American Journal of Clinical Nutrition, 2022

Anne Marie Uwitonze, Mohammed S Razzaque. Role of Magnesium in Vitamin D Activation and Function. J Am Osteopath Assoc. 2018

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