How Vitamin K Could Play a Role in 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.

Tune in to learn how increasing your vitamin K intake could be a simple, non-invasive way to support your brain health.

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

Chapters

• 0:00 Vitamin K in Neuroprotection
• 10:16 Vitamin K and Neurofilament Levels

Transcript

Speaker 1: 0:00

Hello everyone, welcome back to Daily Value. I'm William Wallace, and today we're looking at what I consider to be a topic that deserves to have some more attention brought to it, that being vitamin K and its potential role in neuronal health and neuroprotection. This topic was stimulated by a publication this September in the journal Frontiers in Nutrition 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 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. We will discuss the results of this 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. Just a reminder this podcast is for educational purposes only and is not intended as medical advice. Now let's get started.

Speaker 1: 1:14

So what exactly are neurofilaments? You can think of neurofilaments as scaffolding inside of the neurofibers of brain cells. This helps these cells keep their shape and allows them to function properly. Neurofilaments are particularly important for supporting the structure 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, if you will. Neurofilaments are composed of three subunits, being neurofilament heavy chain, neurofilament medium chain and 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 actual backbone of neurofibers when brain cells are damaged. Neurofilaments light chain is the only of the three that can constitute the actual backbone of neurofibers when brain cells are damaged. Neurofilaments can be released into cerebrospinal fluid and blood. Because neurofilament light chain has a low molecular weight and is 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 are positively associated with stroke risk, as well as dementia risk and dementia-related mortality. As we age, neurofilament levels naturally rise, but higher than expected levels can be an early indicator of neuronal damage and cognitive decline. This makes it a unique marker for assessing brain health, particularly in older populations.

Speaker 1: 2:57

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 it's also important for brain function. Vitamin K exists in two main forms. There's vitamin K1, called phylloquinone, and vitamin K2, also called menaquinone. While vitamin K1 is more commonly found in leafy greens, vitamin K2 is present in fermented foods and some animal products. Vitamin K1 primarily exists as phylloquinone, but there are several different vitamin K2 subtypes. Actually, there are up to 15 different menaquinones, ranging from menaquinone 1, also called MK1, through menaquinone 15, also called MK15.

Speaker 1: 3:43

Although not all vitamin K2 subtypes play a role in human health, the most studied for their effects in humans are MK4 and MK7. Menoquinone 4 is the most abundant vitamin K2 subtype in the human body. Menoquinones are actually made in the body when bacteria in our guts convert vitamin K we take in 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. Vitamin K2, menaquinone 4 specifically, is the main form of vitamin K in the brain. Longer chain menaquinones like MK7 are more bioavailable in the bloodstream but do not accumulate in the brain as significantly as MK4. These forms are more involved in systemic benefits, such as cardiovascular health and bone mineralization, but they may not have brain-specific functions. At least that we know of, the brain has the enzymatic machinery to convert vitamin K1 and longer metaquinones into 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 myelin synthesis, as vitamin K has been shown to modulate sphingolipid metabolism. Sphingolipids are essentially 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 and release of neurofilaments.

Speaker 1: 5:25

A recent study published this September was conducted using data from the National Health and Nutrition Examination Survey, otherwise known as NHANES, and 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 immunoassays 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 either from 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 of vitamin K above 200 micrograms per day. In other words, after reaching a certain threshold, higher vitamin K didn't significantly lower neurofilament light chain levels further, but it also didn't hurt Of note. The authors did not specifically distinguish between vitamin K1 and vitamin K2 intake.

Speaker 1: 6:47

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 for neurodegenerative diseases. Neurofilament light chain is an easily measurable biomarker in blood, meaning that it could 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 or cognitive decline.

Speaker 1: 7:29

How exactly does vitamin K reduce neurofilament light chain levels and protect neurons? Well, there are a couple different potential explanations. One would be 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. Two would be anti-inflammatory effects of vitamin K. Chronic inflammation is 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.

Speaker 1: 8:27

So what does this mean for you? First and foremost, it reinforces the importance of a diet rich in vitamin K. Foods like leafy greens for vitamin K1 and fermented foods like natto for vitamin K2 are excellent sources. Nato for vitamin K2 are excellent sources. Of course, supplements can also provide concentrated forms of vitamin K in the form of vitamin K1 or vitamin K2. You can even find supplements that will provide concentrated doses of different menaquinones, like MK4 and MK7, which are the most common. Remember that MK4 is the form of vitamin K that is most prevalent in the brain and although the study we just discussed did not differentiate between different forms of vitamin K that is 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 might play the largest role in directly supporting brain structure, health and cognitive function, although further research is needed to confirm that. 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 1: 9:42

Do you need to supplement with MK4 to get the potential brain benefits of vitamin K? No, not necessarily. If you take in enough dietary vitamin K and take care of your gut health, you're likely making enough of the various different forms of vitamin K. Worth noting is that there's not an actual recommended dietary allowance established for vitamin K, but there is an adequate intake, also called an AI. That AI is 120 micrograms per day for adult men and 90 micrograms per day for adult women.

Speaker 1: 10:16

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 the relationship, the findings suggest that increasing dietary or supplemental vitamin K might 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 it with others who might benefit. Until next time, stay sharp, stay healthy.