How Vitamin D Intake Might Improve Dementia

Dr. Wiggy has talked over and over again about vitamin D and how good it is.

Now a small study suggests that higher vitamin D supplement intake may be linked to better cognitive function in older adults already showing signs of cognitive decline.

More than 7 million Americans are living with Alzheimer’s dementia, and that number is expected to grow substantially over the coming decades.

This is why researchers are always looking for ways to improve cognitive function

Specifically, they are looking at something known as mild cognitive impairment, or MCI.

MCI causes noticeable changes in memory or thinking but does not always progress to dementia.

Based on findings from researchers at Emory University, there’s a good chance vitamin D can help these patients.

13% Better Performance

Researchers at Emory University studied 54 adults who had MCI

Participants who reported taking at least 5,000 IU of vitamin D per day scored more than 13% higher on a commonly used cognitive test than those who did not take vitamin D.

The findings are interesting. They are also early.

This was a small study, and it cannot show that vitamin D definitively caused the better.

MCI is important to study because it may represent an earlier stage when changes in memory and thinking begin, but significant function remains intact.

Researchers are increasingly interested in whether modifiable factors during this period could help support brain health.

Vitamin D is one of those factors.

The nutrient is best known for its role in bone health, but it also supports nerve and muscle function. Researchers have also been studying its relationship with sleep and brain function.

Sleep deserves attention here because poor sleep and cognitive decline often overlap. Sleep disturbances are common among people with Alzheimer’s disease, and disrupted sleep itself may affect memory and other aspects of brain health.

Participants completed the Montreal Cognitive Assessment, or MoCA, a screening test that measures areas such as memory, attention, language, and executive function.

Those taking at least 5,000 IU of vitamin D daily performed better than participants who did not take vitamin D, even after researchers accounted for other factors.

Lower supplemental doses were not associated with the same improvement in this study.

That doesn’t mean everyone concerned about memory should start taking 5,000 IU a day, either (though that wouldn’t be a bad thing).

Nor did the researchers randomly assign people to receive high-dose vitamin D, since participants were already taking supplements, and they compared reported intake with cognitive scores.

People who take vitamin D may also differ from nonusers in other ways that affect brain health.

The researchers also looked at which form of vitamin D participants used.

Vitamin D2 generally comes from plant or fungal sources, while vitamin D3 can come from animal sources and is also produced in the skin after sun exposure. This is the kind of vitamin D Dr. Wiggy suggests people use. 

In this study, cognitive scores did not differ significantly between people taking D2 and those taking D3.

Again, the study was too small to settle that question. But it suggests that total vitamin D intake may have been more relevant than the form participants chose.

Sleep May Be Part of the Picture

Everyone in the study had some degree of sleep disturbance, which makes the findings especially interesting.

Vitamin D deficiency has previously been associated with problems such as insomnia and nighttime awakenings. At the same time, poor sleep can affect memory, attention and other cognitive functions.

That creates a complicated relationship. Vitamin D, sleep and cognition may influence one another rather than following a simple cause-and-effect path.

The new research does not untangle all of that.

What it does provide is another reason to study vitamin D status in people who have both sleep problems and early cognitive changes.

For patients, the practical takeaway is not to assume that more vitamin D automatically means better memory. Persistent sleep problems or cognitive changes deserve a proper evaluation, and vitamin D status may be one useful piece of that workup.

The study raises a worthwhile possibility. Now larger, controlled studies need to find out whether the connection holds up.