The Forgotten Vitamin for Brain Health

 In today’s episode of Daily Value, we explore the possibly underappreciated role of vitamin K in brain health and neuroprotection. Recent research (doi: 10.3389/fnut.2024.1396707) reveals a connection between dietary vitamin K intake and reduced levels of neurofilament light chain, a potential biomarker for neurodegeneration, particularly in middle-aged and older adults. We’ll discuss how vitamin K supports neuronal function, what specific forms of vitamin K are most important, and how this nutrient might help slow cognitive decline as we age.

Episode Talking Points:

*The role of neurofilament light chain as a biomarker for brain health and its association with neurodegeneration.
*Findings from a recent study (doi: 10.3389/fnut.2024.1396707) showing how higher vitamin K intake (and a specific amount) is linked to lower neurofilament light chain levels.
*The potential of vitamin K, and possibly MK-4, to protect neurons through mechanisms like sphingolipid metabolism and anti-inflammatory effects.

https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1396707/full 

Chapters

• 0:00 Vitamin K and Brain Health
• 9:41 Vitamin K and Brain Health Benefits

Transcript

Speaker 0: 0:00

Hello everyone, welcome back to Daily Value. I'm William Wallace, and today we're looking into what I consider to be a topic that deserves to have some more attention brought to, that found that dietary vitamin K is associated with decreased neurofilament light chain levels, especially in middle-aged and older adults. As for what exactly that is and what it means for brain health with aging, we will get into that momentarily In this episode. We'll talk about neurofilament light chain, what that is and why it's important for brain health and function. We'll discuss vitamin K, specific forms of vitamin K and what role they may play in brain health, as well as structure and function of the brain. We will discuss the results of the study I just mentioned to see what level of vitamin K intake is associated with the most benefit, and we'll discuss the practical implications of these findings in the context of the larger body of research on this topic.

Speaker 0: 1:06

So what exactly are neurofilaments? Well, you can think of neurofilaments as scaffolding inside of the nerve fibers of brain cells. This helps keep these cells shape and structure and allows them to function properly. Neurofilaments are particularly important for supporting the structure of axons. This is the part of axons. This is the part of a neuron that transmits electrical signals between nerve cells. Axons are made up of several components, but neurofilaments are an important component of their cytoskeleton. Neurofilaments are composed of three primary subunits, those being neurofilament heavy chain, neurofilament medium chain and, of course, neurofilament light chain. Neurofilament light chain is the smallest and most abundant subunit of the neurofilaments. Neurofilament light chain is the only of the three that can constitute the backbone of nerve fibers. When brain cells are damaged, neurofilaments can be released into cerebral spinal fluid and blood. Because neurofilament light chain has a very low molecular weight, it's highly soluble. Its levels in cerebral spinal fluid and blood are often considered a biomarker for neurodegeneration. In fact, nervous system diseases are thought to be causal to high peripheral circulating levels of neurofilament light chain. High levels of neurofilament light chain, high levels of neurofilament light chain, are positively associated with stroke risk, as well as dementia and dementia-related mortality. As we age, neurofilament light chain levels naturally increase in our blood, but higher than expected levels can be an early indicator of neuronal damage and cognitive decline. This makes it a unique biomarker for assessing brain health, particularly in older populations.

Speaker 0: 2:48

Now enter vitamin K. Vitamin K is traditionally known for its role in blood clotting and bone health, but research in recent years has suggested its use for brain function. Vitamin K exists in two primary forms vitamin K, also called phylloquinone, and vitamin K2, also called menaquinone. While vitamin K1 is more commonly found in leafy greens, k2 is present in fermented foods and some animal products. Vitamin K1 primarily exists as phylloquinone, but there are several different types of vitamin K2. Actually, there are up to 15 different menoquinones, ranging from menoquinone 1, also called MK1, through menoquinone 15 or MK15. Although not all vitamin K2 subtypes may play a role in human health, the most studied for their effects in humans are MK4 and MK7. Mk4 is the most abundant vitamin K2 subtype in the human body. Metaquinones are actually made in the body when bacteria in our guts convert vitamin K1 from our diet to different forms of vitamin K2. So in this way, gut health is also imperative to health outcomes related to the roles of vitamin K in the body.

Speaker 0: 4:02

Vitamin K2, of vitamin K in the body, vitamin K2, menaquinone 4, specifically, is the primary form of vitamin K in the brain. Longer chain menaquinones like MK7 are more bioavailable in the bloodstream, but they do not accumulate in the brain as significantly as MK4. These forms tend to be more involved in systemic benefits, such as cardiovascular health and bone mineralization and may not have brain-specific functions, at least that we know of. The brain actually has its own enzymatic machinery to convert vitamin K1 and longer-chain menaquinones into vitamin K2, mk4. This indicates the brain's specific requirement for MK4, which explains its dominance in neural tissues and suggests that MK4 has a role in maintaining neurological function, neuroprotection and and myelin synthesis, as vitamin K has been shown to modulate what's called sphingolipid metabolism. Sphingolipids are essential components of myelin, which is the fatty insulating layer that surrounds and protects nerve fibers like axons, which again are structurally held together by neurofilaments, which has led to the hypothesis that vitamin K may influence the stability, health, that vitamin K may influence the stability, health and the release of neurofilaments.

Speaker 0: 5:23

Now a recent study published last year, conducted using data from the National Health and Nutrition Examination Survey, otherwise known as NHANES, aimed to explore the potential relationship between dietary vitamin K intake and serum neurofilament light chain levels in middle-aged and older adults. The study included over 1,500 participants and used highly sensitive amino assays to measure serum neurofilament light chain levels. The findings showed that participants with higher dietary vitamin K intake had significantly lower serum neurofilament light chain levels, particularly those who consumed more than 200 micrograms per day of vitamin K from either food or supplements, or both. The association was stronger in middle-aged and older adults, suggesting that vitamin K might play a protective role in neurodegenerative processes as we age. The dose-response relationship showed that as vitamin K intake increased, neurofilament light chain levels decreased rapidly, but this effect plateaued at intakes above 200 micrograms per day. In other words, after reaching a certain threshold, higher vitamin K intake did not significantly lower neurofilament-like chain levels further, but it also didn't hurt them. Of note, the authors did not specifically distinguish between vitamin K1 and vitamin K2 intake.

Speaker 0: 6:36

This study was interesting for several reasons. First, it adds to the growing body of evidence that diet, and specifically vitamin K intake, can have a profound impact on brain health. Second, it highlights the potential of vitamin K as a neuroprotective agent which could be particularly beneficial for aging populations at risk of neurodegenerative diseases. Neurofilament light chain is an easily measurable biomarker in blood, meaning that it can be used to monitor brain health over time. If future studies confirm that increasing dietary vitamin K can help lower neurofilament light chain levels, it might become a simple, non-invasive way to mitigate the risk of neurodegeneration. But as of now, I do think that a more likely scenario is that vitamin K intake may help to prevent the increase in neurofilament light chain levels as we age.

Speaker 0: 7:25

But how exactly does vitamin K do this? There are a few potential explanations. One, which I mentioned earlier sphingolipid metabolism. Vitamin K plays a role in the synthesis of sphingolipids, which I mentioned earlier. Sphingolipid metabolism Vitamin K plays a role in the synthesis of sphingolipids, which, again, are critical for maintaining the structural integrity of neuronal membranes. Disruption in sphingolipid metabolism has been linked to neurodegenerative diseases, so maintaining proper levels through adequate vitamin K intake might help protect neurons from damage.

Speaker 0: 7:54

Two, there are anti-inflammatory effects of vitamin K. Chronic inflammation is obviously a hallmark of many neurodegenerative diseases. Vitamin K does have anti-inflammatory properties due to its function as a coenzyme for different enzymes in the body, like growth arrest, specific 6 or protein S. These proteins play a role in proliferation of cells and prevent programmed cell death in some cases, which may make them protective proteins. So what does this all mean for you? Well, first and foremost, it reinforces the importance of a diet rich in vitamin K.

Speaker 0: 8:30

Foods like leafy green vegetables for vitamin K1 and fermented foods like natto for vitamin K2 are excellent sources. Of course, supplements can also provide concentrated sources of vitamin K in the form of vitamin K1 or vitamin K2. You can even find supplements that will provide concentrated doses of different metaquinones, like MK4 and MK7, which are the most common. Remember that MK4 is the form of vitamin K that is the most prevalent in the brain and, although the study we just discussed did not differentiate between different forms of vitamin K, we can theorize that this form of vitamin K plays the largest role in directly supporting brain structure, health and cognitive function. That being said, also remember that your body manufactures MK4 from dietary vitamin K1. Brain cells can make MK4 through the conversion of vitamin K1 or other metaquinones. Your microbiota can also convert vitamin K1 into different metaquinones, which highlights a potentially massive role of gut health in maintaining vitamin K status and brain health.

Speaker 0: 9:36

Do you need to supplement with MK4 to get the potential benefits of vitamin K in the brain?

Speaker 0: 9:41

Well, no, not necessarily.

Speaker 0: 9:43

If you've taken enough dietary vitamin K and take care of your gut health, you are likely making enough of the various different vitamin K subtypes.

Speaker 0: 9:50

Worth noting is that there is not an actual recommended dietary allowance of vitamin K, but there is an adequate intake, or AI as it's known, that AI is 120 micrograms a day for adult men and 90 micrograms a day for adult women and 90 micrograms a day for adult women. The study found that neurofilament light chain levels were lowest in individuals who consumed more than 200 micrograms of vitamin K per day, which is above the current adequate intake set for vitamin K for men and women by approximately two-fold. To wrap things up, this new research highlights a very fascinating link between vitamin K intake and lower levels of neurofilament light chain, a key biomarker for neurodegeneration. While more studies are needed to fully understand this relationship, the findings suggest that increasing dietary or supplemental vitamin K may be a simple and effective way to support brain health, particularly in aging populations. Thank you for tuning in to Daily Value. If you found today's episode insightful, be sure to subscribe and share with others who might benefit. Until next time, stay sharp and please stay healthy.