According to a new large-scale study, taking vitamin D supplements can help prevent dementia.
Researchers from the Hotchkiss Brain Institute at the University of Calgary in Canada and the University of Exeter in the UK explored the relationship between vitamin D supplementation and dementia in over 12,388 participants from the US National
In the study published in Alzheimer’s and dementia: diagnosis, evaluation and monitoring of the disease, The team found that taking vitamin D was associated with living a longer dementia-free life, and they also found 40% fewer dementia diagnoses in the group that took the supplements.
Of the entire sample, 2,696 participants progressed to dementia over ten years; of these, 2017 (75%) had no vitamin D exposure during all visits prior to dementia diagnosis, and 679 (25%) had initial exposure.
Professor Zahinoor Ismail, from the University of Calgary and University of Exeter, who led the research, said: ‘We know that vitamin D has effects on the brain which could have implications for reducing dementia, but so far research has yielded conflicting results. . Our results provide key insights into which groups might be specifically targeted for vitamin D supplementation. Overall, we found evidence to suggest that earlier supplementation might be particularly beneficial, before cognitive decline begins.
While vitamin D was effective in all groups, the team found that the effects were significantly greater in women than in men. Similarly, the effects were greater in people with normal cognition, compared with those who reported signs of mild cognitive impairment – changes in cognition that have been linked to a higher risk of dementia.
Recommended daily intake of vitamin D*
|Stage of life||Recommended amount|
|Birth to 12 months||10 mcg (400 IU)|
|Children from 1 to 13 years old||15 mcg (600 IU)|
|Teens 14–18 years old||15 mcg (600 IU)|
|Adults from 19 to 70 years old||15 mcg (600 IU)|
|Adults 71 and over||20 mcg (800 IU)|
|Adolescents and pregnant and breastfeeding women||15 mcg (600 IU)|
The effects of vitamin D were also significantly greater in people who did not carry the APOEe4 gene, which is known to be at higher risk for Alzheimer’s dementia, compared to non-carriers. The authors suggest that people with the APOEe4 gene absorb vitamin D better from their gut, which could reduce the effect of vitamin D supplementation. However, no blood levels were taken to test this hypothesis.
Previous research has shown that low levels of vitamin D are linked to a higher risk of dementia. Vitamin D is involved in the clearance of amyloid in the brain, the accumulation of which is one of the hallmarks of Alzheimer’s disease. Studies have also shown that vitamin D can help protect the brain against the buildup of tau, another protein implicated in the development of dementia.
Co-author Dr Byron Creese, from the University of Exeter, said: “Preventing dementia or even delaying its onset is vitally important given the growing number of people affected. The vitamin D link in this study suggests that taking vitamin D supplements may be beneficial in preventing or delaying dementia, but we now need clinical trials to confirm if this is really the case. The ongoing VitaMIND study at the University of Exeter explores this question in more detail by randomly assigning participants to take vitamin D or a placebo and examining changes in memory and thinking tests over time. .
The VitaMIND study is conducted through PROTECT, an online study open to people aged 40 and over. In PROTECT, annual detailed lifestyle factor questionnaires combine with cognitive testing, to determine what keeps the brain sharp later in life. For more information or to register, visit their website. In Canada, CAN-PROTECT is an online linked study on aging, in people aged 40 and over, with an additional focus on caregiving in dementia.
The study is titled “Gender, Cognitive Status, and APOE Effects for Vitamin D Exposure and Incident Dementia” and is published in Alzheimer’s and dementia: diagnosis, evaluation and monitoring of the disease.
Reference: “Vitamin D supplementation and incident dementia: effects of gender, APOEand baseline cognitive status” by Maryam Ghahremani, Eric E. Smith, Hung-Yu Chen, Byron Creese, Zahra Goodarzi and Zahinoor Ismail, March 1, 2023, Alzheimer’s and dementia: diagnosis, assessment and monitoring of the disease.
*These are average daily recommended amounts according to the US National Institutes of Health (NIH) Office of Dietary Supplements (ODS).