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Study: Vitamin D Supplementation Linked to Drastic Decrease in Dementia Incidence
March 30, 2025
Dementia is unfortunately an increasingly common reality for many older adults around the globe, with some experts estimating that by the year 2060, 1 million U.S. adults will develop dementia each year, up from roughly 514,000 per year as of 2020. Given how difficult and frightening this brain-ravaging condition can be for both patients and their loved ones, researchers continue to look for ways to protect brain health and memory in order to avoid dementia and related conditions, such as Alzheimer’s disease and Parkinson’s disease.
On that front, research from the Alzheimer’s Association highlighted the potential role of vitamin D in reducing the risk of dementia, a condition affecting millions worldwide. A study titled “Vitamin D supplementation and incident dementia: Effects of sex, APOE, and baseline cognitive status” explored this connection, offering insights into how vitamin D supplementation may influence dementia incidence.
Study: Vitamin D for dementia
The study analyzed data from 12,388 dementia-free individuals sourced from the National Alzheimer’s Coordinating Center. Participants had an average age of 71 and were categorized based on their cognitive status as either having normal cognition or mild cognitive impairment.
They were further divided into two groups: those who took vitamin D supplements and those who did not. Researchers tracked these individuals over 10 years, monitoring the onset of dementia.
The findings revealed that vitamin D supplementation was associated with a 40% lower incidence of dementia compared to no supplementation. Specifically, the five-year dementia-free survival rate was 83.6% for the vitamin D group versus 68.4% for the control group.
Among participants with normal cognition, the vitamin D group had a five-year survival rate of 95.3% compared to 89.1% in the control group. For those with mild cognitive impairment, the rates were 49.6% for the supplement group and 34.5% for the control group.
The study also noted that the protective effects of vitamin D were more pronounced in females, individuals with normal cognition and non-carriers of the APOE ε4 gene, a known genetic risk factor for Alzheimer’s disease. This led the study authors to conclude that “Vitamin D has potential for dementia prevention, especially in the high-risk strata.”
This is a huge finding that could have huge ramifications for preventing dementia.
How to get more vitamin D
This research revealed just how important vitamin D can be in protecting cognitive function, and just about everyone can benefit from getting more vitamin D through both sunshine and diet.
How much vitamin D should you get per day? Most adults should get roughly 15 micrograms of vitamin D daily in order to prevent a vitamin D deficiency, and for people over 70 years old, that recommendation increases to 20 micrograms per day.
To maintain optimal vitamin D levels, consider the following sources:
- Sunlight: The body naturally produces vitamin D when exposed to sunlight. Spending 10-30 minutes in the sun a few times a week, depending on skin type and location, can help.
- Dietary sources: Foods rich in vitamin D include fatty fish (salmon, mackerel, tuna), egg yolks, fortified dairy products and mushrooms, among a few others. However, there aren’t many foods that provide a large dose of vitamin D, which is why exposing your skin to sunshine is considered the best way to obtain vitamin D (and why it’s called the “sunshine vitamin”).
- Supplements: Vitamin D supplements (D2 or D3) are widely available and recommended for those with limited sun exposure or dietary intake. Consulting a healthcare provider before starting supplements is advised.
Other vitamin D benefits
Beyond its potential role in reducing dementia risk, vitamin D is recognized for several health benefits, such as:
- Bone health: Vitamin D facilitates calcium absorption, crucial for maintaining strong bones and preventing osteoporosis.
- Immune function: It plays a role in modulating the immune system, potentially reducing the risk of infections and autoimmune diseases.
- Mood regulation: Adequate vitamin D levels have been linked to improved mood and may help alleviate symptoms of depression.
Other potential vitamin D benefits include helping manage blood sugar levels, protect heart health, support skin health and more.
More ways to protect brain health
While vitamin D supplementation appears to help reduce dementia risk, other lifestyle habits also contribute to long-term brain health. Here are some other ways to protect brain health and potentially lower the risk of developing dementia.
- Regular physical exercise: Engaging in aerobic activities like walking, cycling or swimming improves blood flow to the brain and reduces dementia risk.
- Healthy diet: A Mediterranean diet, rich in fruits, vegetables, whole grains, fish and healthy fats, has been linked to better cognitive function.
- Mental stimulation: Keeping the brain active through reading, puzzles, learning new skills or engaging in social activities helps build cognitive resilience.
- Quality sleep: Prioritizing seven to nine hours of sleep per night is essential for memory consolidation and overall brain function.
- Social engagement: Maintaining strong social connections can reduce stress, enhance mood and support cognitive function.
- Managing chronic conditions: Controlling high blood pressure, diabetes and cholesterol levels can lower the risk of vascular dementia.
Conclusion
- The study provides compelling evidence that vitamin D supplementation is associated with a reduced incidence of dementia, particularly among specific subgroups.
- While these findings are promising, further research is necessary to establish causation and determine optimal supplementation strategies. In the meantime, ensuring adequate vitamin D intake remains a prudent approach for overall health and well-being.
- In the meantime, ensuring adequate vitamin D intake through sunlight, diet or supplements remains a prudent approach for overall health and well-being, along with maintaining a brain-healthy lifestyle through exercise, a nutritious diet, mental stimulation and quality sleep.