Study Says Taking Vitamin D Cuts Dementia Risk by 40%—Are Other Factors at Play?
Vitamin D is known for improving bone health, boosting immune function, and improving mood. A new study suggests brain health can be added to that list—as vitamin D supplements may reduce the risk of dementia by 40%.1
The study, published in the journal Alzheimer’s and Dementia: Diagnosis, Assessment, and Disease Monitoring, found that vitamin D supplements showed a protective effect, especially in people with normal cognition and without genetic risk factors for Alzheimer's.1
But don’t run out and buy vitamin D just yet. Experts say that although the research adds to the collective understanding of dementia, it’s not clear how—or if—vitamin D can reduce your chances of developing dementia.
“In these epidemiological studies where you’re looking at groups and comparing them, there’s always this problem of causation,” said Charles Bernick, MD, MPH, a neurologist specializing in Alzheimer’s disease at Cleveland Clinic Lou Ruvo Center for Brain Health.
What Did the Study Show About Vitamin D and Dementia Risk?
Researchers relied on data from the National Alzheimer’s Coordinating Center in Seattle for the study. They examined how 12,388 people who did not have dementia at the start of the study fared over the course of 10 years.
Thirty-seven percent of participants took a vitamin D supplement, and the researchers found there were 40% fewer dementia diagnoses among people in this category.1
While those results sound impressive, it’s unclear why the risk was reduced among study participants who took vitamin D, which leaves the possibilities wide open.
“It could be that people who take [vitamin D] take other vitamins that [reduce the risk], or it could be that maybe if you take vitamins, you exercise more,” Bernick said.
People who take vitamin D may also be more economically advantaged than those who don’t take vitamins, which could affect their health. “There’s all these other factors,” Bernick said. “When you look at one element, it’s hard to know” how influential it is.
That said, this isn’t the first research that has suggested a relationship between vitamin D and dementia risk. A 2014 paper in the journal Neurology concluded that vitamin D deficiency “is associated with a substantially increased risk of all-cause dementia and Alzheimer disease.”
Why Might Vitamin D Reduce Risk for Dementia?
There are several theories on why vitamin D may lower the risk of dementia. One is that vitamin D has anti-inflammatory and antioxidant effects that support brain health, said Peter Gliebus, MD, director of cognitive and behavioral neurology at Marcus Neuroscience Institute.
"Vitamin D supports neurotransmitter function in the brain,” Gliebus said. “Neurotransmitters are vital chemicals that facilitate communication between nerve cells.”
It could also indirectly boost your brain health via your heart. “Vitamin D helps reduce cardiovascular risk, which can enhance blood flow to the brain,” Gliebus added.
What Can You Do To Protect Your Brain Health?
There are a few science-backed ways to reduce your risk of dementia and protect your brain health as you age.
Getting enough exercise is one of the best things you can do, Dr. Bernick said. “The recommendation is to get 150 minutes of moderate-intensity [exercise] a week.”3
Eating a Mediterranean diet and getting a healthy amount of sleep may also help, Dr. Bernick added. A few factors known to increase risk include tobacco and alcohol use, uncontrolled diabetes, and hearing loss, research has shown.4
However, experts stressed there’s likely no one habit or condition that could singlehandedly account for a dementia diagnosis. Instead, a number of health and lifestyle factors are likely involved, and many of them—such as age and genetic makeup—are out of your control.
https://www.verywellhealth.com/vitamin-d-and-dementia-risk-8777535