This Supplement Could Protect Your Brain from Dementia, New Study Suggests
Key Points
As rates of dementia and Alzheimer’s disease continue to rise, many people are looking for ways to protect their brain health as they age. While genetics can play a role in whether or not you develop the condition, lifestyle factors such as nutrition are being studied for their potential impact on cognitive function later in life.
Emerging research suggests that vitamin D—which you may associate more with bone health and immune function—may also protect your brain from cognitive decline. A new study published in Neurology Open Access suggests that vitamin D levels in midlife could be linked to changes in the brain associated with dementia years later. Here’s what you need to know.
How Was This Study Conducted?
Researchers analyzed data from 793 adults who were part of the Framingham Heart Study Generation 3 cohort. At the start of the study (between 2002 and 2005), participants were around 39 years old on average and were free of dementia. At that time, researchers measured each participant’s blood levels of vitamin D. Roughly 16 years later, participants underwent brain scans to evaluate levels of tau and amyloid beta—two proteins associated with Alzheimer’s disease.
Vitamin D levels above 30 nanograms per milliliter were considered higher, while levels below that threshold were classified as lower. In this group, about 34% of participants had lower vitamin D levels, and only about 5% reported taking vitamin D supplements. To better isolate the relationship, researchers adjusted for factors that can influence brain health, including age, sex, smoking status, blood pressure, diabetes and body mass index.
What Did This Study Find?
Researchers found an association between vitamin D levels in midlife and brain health years later:
- People with higher vitamin D levels had lower levels of tau protein in the brain about 16 years later.
- Vitamin D levels were not associated with amyloid beta, another Alzheimer’s-related protein.
- The findings suggest a potential link between vitamin D status and early brain changes linked to dementia.
“These results suggests that higher vitamin D levels in midlife may offer protection against developing these tau deposits in the brain and that low vitamin D levels could potentially be a risk factor that could be modified and treated to reduce the risk of dementia,” said study author Martin David Mulligan, a Ph.D. candidate at the University of Galway.
Tau buildup in the brain is linked to Alzheimer’s disease and cognitive decline, making it a critical biomarker in dementia research. Lower levels of tau may indicate healthier brain aging, though more research is needed to fully understand the relationship. However, the researchers note these findings show an association only—not clear proof that vitamin D directly reduces dementia risk.
Limitations
While the study’s results are promising, there are several limitations to consider. Vitamin D levels were measured only once at the beginning of the study. Researchers did not track changes in vitamin D status over time, which could affect long-term outcomes.
Additionally, this was an observational study, meaning it can identify patterns but cannot establish cause and effect. It’s possible that people with higher vitamin D levels also had other health behaviors that contributed to better brain health. Although researchers adjusted for many variables, unmeasured factors may still have influenced the results.
How Does This Apply to Real Life?
This study highlights midlife as a crucial time in your life for supporting long-term brain health. “These results are promising, as they suggest an association between higher vitamin D levels in early middle age and lower tau burden on average 16 years later,” Mulligan said. “Midlife is a time where risk factor modification can have a greater impact.”
You can obtain vitamin D through sunlight exposure, certain foods and supplements. Foods that contain vitamin D include fatty fish like salmon and sardines, fortified dairy or plant-based milks and egg yolks.
While this study doesn’t prove that taking a vitamin D supplement will prevent dementia, maintaining adequate levels can be one piece of the broader brain-health puzzle. If you’re concerned about your vitamin D status, speak with your health care provider or a registered dietitian about testing or supplementation.
Our Expert Take
A long-term study recently published in Neurology Open Access suggests that vitamin D levels in midlife may be linked to early brain changes associated with Alzheimer’s disease and dementia. While the findings don’t prove that vitamin D prevents dementia, they add to growing evidence that nutrition and lifestyle factors in midlife can affect long-term brain health and cognitive function. Maintaining sufficient vitamin D levels, along with other healthy lifestyle habits, can help support brain health and reduce dementia risk as you age.