Episode Transcript
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Speaker 0 (00:00):
Hello everyone,
welcome back to Daily Value.
I'm William Wallace, and todaywe're looking into what I
consider to be a topic thatdeserves to have some more
attention brought to, that foundthat dietary vitamin K is
associated with decreasedneurofilament light chain levels
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, especially in middle-aged andolder adults.
As for what exactly that is andwhat it means for brain health
with aging, we will get intothat momentarily In this episode
.
We'll talk about neurofilamentlight chain, what that is and
why it's important for brainhealth and function.
We'll discuss vitamin K,specific forms of vitamin K and
what role they may play in brainhealth, as well as structure
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and function of the brain.
We will discuss the results ofthe study I just mentioned to
see what level of vitamin Kintake is associated with the
most benefit, and we'll discussthe practical implications of
these findings in the context ofthe larger body of research on
this topic.
So what exactly areneurofilaments?
Well, you can think ofneurofilaments as scaffolding
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inside of the nerve fibers ofbrain cells.
This helps keep these cellsshape and structure and allows
them to function properly.
Neurofilaments are particularlyimportant for supporting the
structure of axons.
This is the part of axons.
This is the part of a neuronthat transmits electrical
signals between nerve cells.
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Axons are made up of severalcomponents, but neurofilaments
are an important component oftheir cytoskeleton.
Neurofilaments are composed ofthree primary subunits, those
being neurofilament heavy chain,neurofilament medium chain and,
of course, neurofilament lightchain.
Neurofilament light chain isthe smallest and most abundant
subunit of the neurofilaments.
Neurofilament light chain isthe only of the three that can
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constitute the backbone of nervefibers.
When brain cells are damaged,neurofilaments can be released
into cerebral spinal fluid andblood.
Because neurofilament lightchain has a very low molecular
weight, it's highly soluble.
Its levels in cerebral spinalfluid and blood are often
considered a biomarker forneurodegeneration.
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In fact, nervous systemdiseases are thought to be
causal to high peripheralcirculating levels of
neurofilament light chain.
High levels of neurofilamentlight chain, high levels of
neurofilament light chain, arepositively associated with
stroke risk, as well as dementiaand dementia-related mortality.
As we age, neurofilament lightchain levels naturally increase
in our blood, but higher thanexpected levels can be an early
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indicator of neuronal damage andcognitive decline.
This makes it a uniquebiomarker for assessing brain
health, particularly in olderpopulations.
Now enter vitamin K.
Vitamin K is traditionallyknown for its role in blood
clotting and bone health, butresearch in recent years has
suggested its use for brainfunction.
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Vitamin K exists in two primaryforms vitamin K, also called
phylloquinone, and vitamin K2,also called menaquinone.
While vitamin K1 is morecommonly found in leafy greens,
k2 is present in fermented foodsand some animal products.
Vitamin K1 primarily exists asphylloquinone, but there are
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several different types ofvitamin K2.
Actually, there are up to 15different menoquinones, ranging
from menoquinone 1, also calledMK1, through menoquinone 15 or
MK15.
Although not all vitamin K2subtypes may play a role in
human health, the most studiedfor their effects in humans are
MK4 and MK7.
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Mk4 is the most abundantvitamin K2 subtype in the human
body.
Metaquinones are actually madein the body when bacteria in our
guts convert vitamin K1 fromour diet to different forms of
vitamin K2.
So in this way, gut health isalso imperative to health
outcomes related to the roles ofvitamin K in the body.
Vitamin K2, of vitamin K in thebody, vitamin K2, menaquinone 4,
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specifically, is the primaryform of vitamin K in the brain.
Longer chain menaquinones likeMK7 are more bioavailable in the
bloodstream, but they do notaccumulate in the brain as
significantly as MK4.
These forms tend to be moreinvolved in systemic benefits,
such as cardiovascular healthand bone mineralization and may
not have brain-specificfunctions, at least that we know
of.
The brain actually has its ownenzymatic machinery to convert
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vitamin K1 and longer-chainmenaquinones into vitamin K2,
mk4.
This indicates the brain'sspecific requirement for MK4,
which explains its dominance inneural tissues and suggests that
MK4 has a role in maintainingneurological function,
neuroprotection and and myelinsynthesis, as vitamin K has been
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shown to modulate what's calledsphingolipid metabolism.
Sphingolipids are essentialcomponents of myelin, which is
the fatty insulating layer thatsurrounds and protects nerve
fibers like axons, which againare structurally held together
by neurofilaments, which has ledto the hypothesis that vitamin
K may influence the stability,health, that vitamin K may
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influence the stability, healthand the release of
neurofilaments.
Now a recent study publishedlast year, conducted using data
from the National Health andNutrition Examination Survey,
otherwise known as NHANES, aimedto explore the potential
relationship between dietaryvitamin K intake and serum
neurofilament light chain levelsin middle-aged and older adults
.
The study included over 1,500participants and used highly
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sensitive amino assays tomeasure serum neurofilament
light chain levels.
The findings showed thatparticipants with higher dietary
vitamin K intake hadsignificantly lower serum
neurofilament light chain levels, particularly those who
consumed more than 200micrograms per day of vitamin K
from either food or supplements,or both.
The association was stronger inmiddle-aged and older adults,
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suggesting that vitamin K mightplay a protective role in
neurodegenerative processes aswe age.
The dose-response relationshipshowed that as vitamin K intake
increased, neurofilament lightchain levels decreased rapidly,
but this effect plateaued atintakes above 200 micrograms per
day.
In other words, after reachinga certain threshold, higher
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vitamin K intake did notsignificantly lower
neurofilament-like chain levelsfurther, but it also didn't hurt
them.
Of note, the authors did notspecifically distinguish between
vitamin K1 and vitamin K2intake.
This study was interesting forseveral reasons.
First, it adds to the growingbody of evidence that diet, and
specifically vitamin K intake,can have a profound impact on
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brain health.
Second, it highlights thepotential of vitamin K as a
neuroprotective agent whichcould be particularly beneficial
for aging populations at riskof neurodegenerative diseases.
Neurofilament light chain is aneasily measurable biomarker in
blood, meaning that it can beused to monitor brain health
over time.
If future studies confirm thatincreasing dietary vitamin K can
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help lower neurofilament lightchain levels, it might become a
simple, non-invasive way tomitigate the risk of
neurodegeneration.
But as of now, I do think thata more likely scenario is that
vitamin K intake may help toprevent the increase in
neurofilament light chain levelsas we age.
But how exactly does vitamin Kdo this?
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There are a few potentialexplanations.
One, which I mentioned earliersphingolipid metabolism.
Vitamin K plays a role in thesynthesis of sphingolipids,
which I mentioned earlier.
Sphingolipid metabolism VitaminK plays a role in the synthesis
of sphingolipids, which, again,are critical for maintaining
the structural integrity ofneuronal membranes.
Disruption in sphingolipidmetabolism has been linked to
neurodegenerative diseases, somaintaining proper levels
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through adequate vitamin Kintake might help protect
neurons from damage.
Two, there are anti-inflammatoryeffects of vitamin K.
Chronic inflammation isobviously a hallmark of many
neurodegenerative diseases.
Vitamin K does haveanti-inflammatory properties due
to its function as a coenzymefor different enzymes in the
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body, like growth arrest,specific 6 or protein S.
These proteins play a role inproliferation of cells and
prevent programmed cell death insome cases, which may make them
protective proteins.
So what does this all mean foryou?
Well, first and foremost, itreinforces the importance of a
diet rich in vitamin K.
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Foods like leafy greenvegetables for vitamin K1 and
fermented foods like natto forvitamin K2 are excellent sources
.
Of course, supplements can alsoprovide concentrated sources of
vitamin K in the form ofvitamin K1 or vitamin K2.
You can even find supplementsthat will provide concentrated
doses of different metaquinones,like MK4 and MK7, which are the
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most common.
Remember that MK4 is the formof vitamin K that is the most
prevalent in the brain and,although the study we just
discussed did not differentiatebetween different forms of
vitamin K, we can theorize thatthis form of vitamin K plays the
largest role in directlysupporting brain structure,
health and cognitive function.
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That being said, also rememberthat your body manufactures MK4
from dietary vitamin K1.
Brain cells can make MK4through the conversion of
vitamin K1 or other metaquinones.
Your microbiota can alsoconvert vitamin K1 into
different metaquinones, whichhighlights a potentially massive
role of gut health inmaintaining vitamin K status and
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brain health.
Do you need to supplement withMK4 to get the potential
benefits of vitamin K in thebrain?
Well, no, not necessarily.
If you've taken enough dietaryvitamin K and take care of your
gut health, you are likelymaking enough of the various
different vitamin K subtypes.
Worth noting is that there isnot an actual recommended
dietary allowance of vitamin K,but there is an adequate intake,
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or AI as it's known, that AI is120 micrograms a day for adult
men and 90 micrograms a day foradult women and 90 micrograms a
day for adult women.
The study found thatneurofilament light chain levels
were lowest in individuals whoconsumed more than 200
micrograms of vitamin K per day,which is above the current
adequate intake set for vitaminK for men and women by
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approximately two-fold.
To wrap things up, this newresearch highlights a very
fascinating link between vitaminK intake and lower levels of
neurofilament light chain, a keybiomarker for neurodegeneration
.
While more studies are neededto fully understand this
relationship, the findingssuggest that increasing dietary
or supplemental vitamin K may bea simple and effective way to
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support brain health,particularly in aging
populations.
Thank you for tuning in toDaily Value.
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Until next time, stay sharp andplease stay healthy.