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INYANGA HEALTH

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Writer's pictureDr. Alex Armitage

Can Vitamin D Keep Your Mind Sharp? What the Science Says About Cognition


  • New studies are shining a light on the incredible potential of Vitamin D as a frontline defense in protecting cognition.

  • Folks with healthy cognitive function who got a helping hand from vitamin D experienced a whopping 56% reduction in the risk of developing dementia.

  • Intriguingly, the benefits were most noticeable in women, individuals with no signs of cognitive issues, and those who don't carry the APOE ε4 gene variant, a known risk factor for dementia.

  • The type of vitamin D supplementation does not seem to matter


Man on a beach at sunrise, with arms held high

If you've ever enjoyed a sunny day at the beach, you've experienced nature's way of giving you a vitamin D boost. Known as the "sunshine vitamin," vitamin D is fat-soluble and is primarily formed when our skin is exposed to sunlight. But sunshine isn't just good for your mood; there's a growing body of research suggesting that adequate levels of vitamin D might have a protective effect against the onset of dementia.


Why Vitamin D Matters

First things first, why is vitamin D important? Your body needs it for a variety of functions: from helping your bones absorb calcium to playing a role in immune system regulation. But we're increasingly understanding that its benefits might extend to cognitive health as well.


Understanding Vitamin D's Role in Protecting Cognition

Let's face it, dementia is a global concern. More than 50 million people worldwide are navigating life with this condition, and sadly, that number is projected to triple by the year 2050. Right now, we don't have a magical pill that can halt or turn back the clock on dementia's progress. The older medications on the market for cognition are modest at best, and some of the newer medications that are coming to market carry significant risk, are FDA approved only for early-stage cognitive decline and have yet to definitively been proven useful to help improve thinking, as the end-point in the FDA trials has been amyloid plaque reduction and not cognitive improvement – which are not the same thing! So, medical experts are looking into other ways, like modifying certain risk factors, to slow down the disease.


Now, where does vitamin D come into play? Well, vitamin D deficiency is a surprisingly common issue, affecting almost 1 billion people globally. And here's the kicker: vitamin D is thought to play a role in clearing out some of the damaging build-up in the brain linked to Alzheimer's disease—specifically, those sticky clusters known as amyloid beta.


Vitamin supplements

A Hot Topic: Does Vitamin D Supplementation Help Cognition?

However, the million-dollar question is: Can taking vitamin D supplements actually help? Previous studies give us a mixed bag of results. Some show promising signs that vitamin D supplements can improve brain function, while others say there's not enough evidence to back this claim. This discrepancy could be due to various factors like different dosages used in the trials, the duration of the study, or even the size of the study group.

The Link Between Vitamin D and Cognition: Past and present research

Several observational studies have indicated that low levels of vitamin D are associated with a higher risk of developing cognitive impairment and dementia. A study published in the journal "Neurology" in 2014 found that adults who had moderate to severe vitamin D deficiencies had a 53% increased risk of developing dementia (see the bottom of this article for the complete references, Littlejohns, et al., 2014).


A new study suggests that vitamin D supplementation can cut the risk of dementia by as much as 40 %. The study was published online March 1, 2023 in Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring (Ghahremani et al., 2023).


In this recent study, the researchers wanted to get to the bottom of the controversy over Vitamin D supplementation. They looked at older adults who were free of dementia and studied the effects of different types of vitamin D supplements over time (10 years). They considered various factors such as age, medical history, lifestyle, and even genetics. Their working theory was simple: They believed that any kind of vitamin D supplement could potentially lower the risk of developing dementia.


Exposure to vitamin D supplementation was associated with an average 40% lower dementia incidence rate than no exposure, providing strong support for supplementation. The results were consistent across three vitamin D formulations. The effect of vitamin D exposure on the rate of incident dementia differed significantly across the strata of sex, cognitive status, and apolipoprotein E (APOE) ε4 status.


Woman going for a walk in the sun

How Timing Could Make a Difference: Vitamin D and Your Brain

So, what happens when we start looking at the benefits of vitamin D at different stages of cognitive health? Well, it gets fascinating! For people who have normal cognitive function and those experiencing some mild memory issues—what we call mild cognitive impairment or MCI—the picture is optimistic.


The findings show that folks with healthy cognitive function who got a helping hand from vitamin D experienced a whopping 56% reduction in the risk of developing dementia. Those in the mild memory issue category, or MCI, saw a 33% risk reduction compared to those who weren't taking vitamin D supplements. Across the board, regardless of the type of vitamin D formulation used, the story was the same: Vitamin D appears to be a good friend to our brain.


Why Early Action Could Be Crucial

Now, why is this so important? If vitamin D helps in cleaning up those harmful clusters in our brain, it makes sense to think that starting supplementation earlier could give us a better shot at slowing down this ugly cascade of events that leads to more severe memory issues. By the time someone has already developed MCI, there might be multiple factors at play, making it more challenging for vitamin D alone to serve as a silver bullet.

The Intricacies of Vitamin D, Sex, Depression, and Genetic Factors in Dementia Risk

The Estrogen Connection

Interestingly, while both men and women seem to benefit from vitamin D when it comes to lowering the risk of dementia, women appear to get an extra edge. What’s going on here?

Well, it could have something to do with estrogen, the hormone that's more abundant in females. Research shows that estrogen might actually help our bodies better use vitamin D by increasing the activity of the enzymes that activate it. Now, here's where it gets a bit complex but also intriguing. As women age and go through menopause, estrogen levels decline. This decrease could act like a double roadblock, hindering our ability to make the most out of vitamin D.


Laughing woman

Thinking and mood

Let’s talk about the mood factor. While being depressed was linked to a 35% higher chance of developing dementia, adding vitamin D into the mix didn’t make a noticeable difference. In simple terms, if you're feeling blue, vitamin D alone might not be the magic fix when it comes to lowering dementia risk.


A Twist in the Tale: The Role of Genetics

Now, let’s delve into something a bit more complex: genetics, specifically a genetic marker called APOE ε4. This marker is like a red flag, signaling a higher risk of developing Alzheimer’s. Interestingly, people with this marker seemed to naturally have more vitamin D in their system. Even though everyone benefited from vitamin D supplementation, those without the APOE ε4 marker saw more significant improvements. Why? Well, it could be because those with the marker already have a somewhat higher baseline level of vitamin D, so the supplements don't make as big of a difference. Or it might be that the genetic risk is so high that vitamin D alone can’t fully counteract it.


What The Study Did Not Tell Us

The study did not measure baseline Vitamin D levels in participants, and did not record the dose of vitamin D that was being taken in any participants.


What Type of Vitamin D Should I Take?

Not all vitamin D supplements are created equal. The most commonly used type in clinical trials is cholecalciferol (vitamin D3 found in the supermarket), followed by another form called ergocalciferol (vitamin D2, a prescription medication.) While many think these two are interchangeable, recent findings suggest that cholecalciferol may be better at maintaining good vitamin D levels in your body. This is worth repeating and let me phrase this in a different was: The over-the-counter vitamin D (D3) that you buy at the pharmacy is a better option for maintaining your vitamin levels than the prescription (D2) supplement that your doctor can give you. This is not what you may expect, but there you have it!

A selection of vitamin capsules

It is good to know though, that when it comes to the type of vitamin D supplement, this recent study found that they all did a decent job of lowering dementia risk. So, whether it’s cholecalciferol (D3), ergocalciferol (D2), or a calcium-vitamin D combo, each formulation showed promise in keeping dementia at bay.

How Could Vitamin D Help Thinking? Here's the Science...

When it comes to the brain, think of vitamin D as a sort of "maintenance worker" that helps to keep things running smoothly.


First, vitamin D is implicated in the regulation of amyloid-beta proteins. These proteins can accumulate in the brain and are one of the hallmarks of neurodegenerative diseases such as Alzheimer's. Think of these proteins like debris clogging a drain; they disrupt cellular communication when they aggregate. Vitamin D aids the body's mechanisms in effectively clearing these obstructions, thus supporting neural networks.

Additionally, vitamin D exhibits neuroprotective qualities through its anti-inflammatory and antioxidative properties. Imagine your brain cells are akin to a well-constructed edifice. Over time, factors such as oxidative stress and inflammation act like natural elements that wear down the structure. Vitamin D serves as a kind of safeguard, protecting against this gradual deterioration.


Now, let's turn our attention to neurons, the core components of your nervous system. Vitamin D supports both the maintenance and the formation of new neurons, functioning somewhat like a quality assurance manager in a factory. This process ensures that your cognitive network remains robust and efficient.


There's also an interesting interplay between vitamin D and tau proteins. In a healthy state, tau proteins stabilize microtubules in the neurons, akin to the beams in a building's structure. However, pathological changes lead to tau hyperphosphorylation, a process reminiscent of a building's framework corroding over time. Vitamin D appears to offer some level of protection against this process, helping to keep the infrastructure intact.



Taking Charge of Your Vitamin D Levels: Simple Steps for a Healthier Future

Now that we've piqued your interest, you're probably wondering, "How do I get enough of this amazing vitamin?" There are a few simple yet effective ways to do so:


Step Outside: The Sunshine Vitamin Awaits

Ah, the sun—the original vitamin D factory. Just 10 to 30 minutes of sun exposure between 10 a.m. and 3 p.m. a couple of times a week can help boost your levels. Now, I'm not saying go out and bake yourself; you can still wear a hat and apply sunscreen to your face, but maybe let your arms or legs soak up those rays.


A poached egg of avocado toast

On the Menu: Vitamin D-Rich Foods

Let's talk about how you can eat your way to better vitamin D levels. Fatty fish like salmon, mackerel, and sardines are chock-full of it. Eggs (specifically the yolk) and fortified foods like certain cereals and orange juice can also help. So, consider having salmon for dinner or adding a glass of fortified orange juice to your breakfast. Your brain might just thank you later.


Supplements: The Extra Boost

If you live somewhere where sunshine is scarce or you're just not a fish person, supplements are a reliable alternative. Now, before you start popping pills, consult with your healthcare provider, as too much vitamin D can have its own side effects. Once you get the green light, you'll find various forms like cholecalciferol (Vitamin D3) and ergocalciferol (Vitamin D2) available.


Listen to Your Body: Testing and Tailoring

It's a good idea to get your vitamin D levels checked, especially as you age or if you have a history of bone or cognitive issues. Based on the results, your healthcare provider can recommend the right dose to either correct a deficiency or maintain optimal levels. In fact, some may recommend periodic testing to adjust your intake as needed.


In Conclusion

The relationship between vitamin D and dementia is an exciting area of study that's still unraveling. While we can't say for sure that it's a foolproof preventative measure, it's one more compelling reason to keep an eye on your vitamin D levels. As always, the best healthcare approach is a holistic one, taking into consideration multiple aspects of well-being.


Investing in your health by maintaining balanced vitamin D levels could be a step towards not only stronger bones and a healthier body but perhaps a sharper mind as well. So, why not seize the day and, quite literally, soak up some sunshine?

Remember, every ray of sunlight could potentially be a ray of hope in maintaining cognitive health. It's an investment worth making!




The articles that sparked interest for this blog article were:

Ghahremani, M., Smith, E. E., Chen, H.-Y., Creese, B., Goodarzi, Z., & Ismail, Z. (2023). Vitamin D supplementation and incident dementia: Effects of sex, APOE, and baseline cognitive status. Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring. https://doi.org/10.1002/dad2.12404


Littlejohns, T. J., Henley, W. E., Lang, I. A., Annweiler, C., Beauchet, O., Chaves, P. H. M., Fried, L., Kestenbaum, B. R., Kuller, L. H., Langa, K. M., Lopez, O. L., Kos, K., Soni, M., & Llewellyn, D. J. (2014). Vitamin D and the risk of dementia and Alzheimer disease. Neurology, 83(10), 920-928. https://doi.org/10.1212/WNL.0000000000000755

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