If we asked you what the first five vitamins and minerals that come to your mind are, what would your answer be? Vitamin D, vitamin C, magnesium, potassium, calcium, maybe zinc… how about vitamin K?
For most people, vitamin K doesn’t hit their radar. It’s a vitamin that we know is essential, but it often gets shoved into the corner and doesn’t quite hit the spotlight.
But it’s about time that changes. While it may not hold the title of the super-vitamin of the year, vitamin K has some pretty important functions that make it a must in any diet - and supplement stack.
Whether it's blood clotting, bone metabolism, or calcium homeostasis, your body needs an adequate intake of vitamin K. Without it, you’re walking down a dangerous path.
If you’re not familiar with the nutrient and it hasn’t hit your stack yet, we’re covering the basics of why vitamin K is important, what to look out for if a vitamin K deficiency develops, and where you can find the best vitamin K supplement.
What Is Vitamin K?
Vitamin K, which is a group of fat-soluble vitamins, plays critical roles in several essential body functions ranging from bone health to blood clotting. Although there are several forms of vitamin K, two are especially important to humans: K1 and K2.
Here’s something you probably have never thought about: how did people learn about vitamins?
Vitamin K discovery dates back to the 1920s when a scientist discovered that restricting specific components from a chick’s diet led to internal hemorrhaging and other symptoms similar to scurvy but weren’t fixed by large doses of vitamin C 1.
The scientist tried several other options to treat the tricks, but the only food that worked was cereal grains, which he found offered protective effects. This prompted him to conclude that insufficient levels of an essential dietary component caused the bleeding, and it wasn’t vitamins A, D, or C.
Further research found that particular plant and animal foods contained a compound that stopped the bleeding; this antihemorrhagic factor was a newly discovered fat-soluble vitamin called “Koagulations vitamin” or vitamin K.
Because there are several types of vitamin K, each is named based on the length of the side chain. Vitamin K1 is termed phylloquinone, while vitamin K2 is called menaquinone and comes in multiple forms.
Menaquinone-7 (MK‐7) is commonly found in fermented vegetable products, and menaquinone-4 (MK-4) is common in many animal products. You’ll also see other menaquinones, such as MK-5 and MK-6.
The primary function of vitamin K is as a cofactor for vitamin K-dependent proteins (VKDP) that require carboxylation to elicit their activity. This means vitamin K intake is the rate-limiting factor for these reactions2, and insufficient intake of vitamin K can interfere with them.
But what’s the actual difference between K1 and K2?
Vitamin K1 vs. K2
Naturally occurring vitamin K compounds found in plant foods like green leafy vegetables are named phylloquinone or vitamin K1. There are also several bacterial-derived menaquinones (MKs) that form vitamin K2, found in animal-based food products and fermented foods 3.
While the basic structure of vitamin K is similar, the side chains differentiate these quinones. They dictate how the K vitamins are metabolized, including their transport, target tissue uptake, and excretion.
The important menaquinones you’ll want to know about are the short-chain MK-4, found in animal foods like eggs, meat, and liver, and long-chain menaquinones MK-7, MK-8, MK-9, and MK-10, which are found in fermented foods such as cheese, curd, sauerkraut, and natto 4.
We’ll talk about the benefits of vitamin K shortly, but there are some differences in functions between K1 and K2.
Menaquinones like MK-7 have a more significant and longer-lasting effect on blood coagulation than K1 or MK-4 4. Compared to K1, MK-7 has a longer half-life and elicits a more long-term effect. But studies show that K2 also offers benefits to bone and cardiovascular health.
But there’s another difference: uptake site. Plant-based K1 is taken up mainly in the liver, while vitamin K2 preferentially accumulates in arteries and extrahepatic (outside the liver) locations 2.
Benefits Of Vitamin K
Promotes blood clotting
Perhaps the most prominent role of vitamin K is in blood coagulation. Vitamin K is required to form four of the 13 proteins needed for the blood clotting cascade, which puts the breaks on an open and continuously bleeding wound.
A vitamin K deficiency leads to a potential acute, life-threatening condition due to excessive vitamin K deficiency bleeding 5.
Your body needs vitamin K for the formation of several pro-blood clotting proteins called factors II (prothrombin), VII, IX, and X, which form the basis of the coagulation cascade; it’s also required for anticoagulant proteins called proteins C, S, and Z 5.
All these proteins are necessary for blood to coagulate and wounds to heal. However, although the coagulation process is required to prevent bleeding, some people have blood clot disorders where their blood clots too easily - this is why we have drugs like Warfarin and other blood thinner medications.
These drugs function by antagonizing the action of vitamin K. But remember that if you’re on blood thinners, excessive vitamin K intake can interfere with these medications.
Supports healthy bones
When it comes to bone mass and integrity, we usually think about vitamin D and calcium - but vitamin K also plays a role in healthy bones via calcium metabolism.
Vitamin K2 is required to activate two proteins with calcium-binding actions - matrix GLA protein (MGP) and osteocalcin—both involved in building and maintaining bone tissue 6, 7.
A fair bit of research shows that vitamin K increases bone mineral density in osteoporotic people and can also reduce fracture rates 8. Although there are several mechanisms for vitamin K’s effect on bone metabolism, there are two we focus on:
- Gamma-carboxylation of osteocalcin, an essential protein involved in bone mineralization
- Vitamin K’s effect on calcium homeostasis
Studies show that impaired function of osteocalcin and MGP due to incomplete carboxylation from insufficient vitamin K levels increases the risk of osteoporosis and vascular calcification 9.
Simply put, vitamin K must be present for gamma-glutamyl carboxylase to support the function of osteocalcin through a process called carboxylation, which is essential for bone growth.
May improve memory
Vitamin K for cognitive function? Yep, you read that right.
Although you won’t typically see vitamin K at the top of any brain-boosting supplement, that doesn’t mean it has nothing to offer.
The VKDPs that require sufficient levels of vitamin K for optimal function aren’t just involved in bone health. The VKDPs that don’t contribute to bone or bleeding are involved in the metabolism of sphingolipids, a class of lipids found in brain cell membranes 10.
Alterations in sphingolipid metabolism have been implicated in age-related cognitive decline and neurodegenerative conditions such as Alzheimer’s 11.
On the other hand, some research suggests that vitamin K-antagonists, like those used in anticoagulants, may adversely affect visual memory, verbal fluency, and brain volume 12.
Normalizes blood pressure
Diet and exercise are two biggies involved in regulating blood pressure, but nutrient deficiencies can also play a role - especially a vitamin K deficiency.
Vitamin K may support a healthy cardiovascular system by reducing the risk of hypertension and cardiovascular disease.
While diet and exercise play a significant role in reducing blood pressure and improving cardiovascular health, so does vitamin K. It’s important for supporting heart health and may reduce the risk of hypertension and cardiovascular disease.
Low levels of vitamin K and vitamin D have been linked to an increased risk of cardiovascular events due to a joint interaction between the two nutrients and vascular health 13.
Studies find that low vitamin D and K levels are linked to systolic and diastolic blood pressure increases, likely due to the interaction between vitamin K and D in regulating blood levels.
On top of that, we also look at vascular calcification—a process where minerals like calcium are deposited in blood vessels and, over time, become calcified, thereby blocking blood flow.
Vascular calcification is common during aging, but getting enough vitamin K can prevent mineralization, thus fending off this process and keeping blood vessels healthy and blood pressure normal.
Reduces the risk of heart disease
Piggybacking on the above benefit, vitamin K is also beneficial for reducing the risk of heart disease - the leading cause of death in the United States.
17 vitamin K-dependent proteins regulate soft-tissue calcification, and all require vitamin K-dependent carboxylation to elicit their activity 14.
But here’s the thing: supplementing vitamin K2 can significantly affect your risk level.
A 2004 study found that people with the highest intake of vitamin K2 were 52% less likely to develop arterial calcification and had a massive 57% lower risk of dying from heart disease 15.
So, what’s the solution for keeping a healthy heart? Load up on the K.
What Causes A Vitamin K Deficiency?
While there are many foods rich in vitamin K1 and K2, getting enough through diet can sometimes be challenging due to dietary restrictions or preferences - vitamin K2 is naturally found in foods that some people might turn their nose to, such as sauerkraut, natto, and cheese curds.
Vitamin K deficiency can result from several reasons, including16:
- Neonatal vitamin K deficiency
- Hereditary combined vitamin K-dependent clotting factors deficiency (VKCFD)
- Inadequate dietary uptake or insufficient dietary intake
- Chronic health disorders (fat malabsorption syndromes, etc.)
- Drug-related/antibiotic use
Vitamin K Deficiency Symptoms To Know About
If you suspect you may not be fulfilling your daily requirements for vitamin K, excessive bleeding issues are generally one of the major signs to look out for.
Bleeding or hemorrhaging in healthy adults is one of the most obvious signs of low vitamin K levels and often comes from the nose, a wound, stomach, or an intestine.
If you have a vitamin K deficiency, here are the five cardinal signs to watch out for:
Easy bruising
Bleeding and easy bruising are cardinal signs of a vitamin K deficiency.
Because vitamin K is required for the γ-carboxylation of glutamic acid residues of coagulant factors II, VII, IX, and X, insufficient vitamin K levels interfere with these factors' activity and lead to bleeding 17.
Small blood clots underneath the nails
While subungual hematomas often occur due to trauma to the nails, they can also arise due to low vitamin K levels.
Blood clots typically appear as small, dark spots (dark red or black/purpose) along the base of the nail bed.
Bleeding in mucous membranes that line areas inside the body
Lack of coagulant factors needed for blood to clot inside the body can lead to excessive bleeding from areas like the gastrointestinal tract, epistaxis, bleeding gums, menorrhagia, etc.
Dark black, tar-like stool that contains blood
Bleeding from mucosal tissues, especially within the gastrointestinal tract, can lead to black, tarry-looking stools discolored from dried blood.
Weakened bones (increased risk of fractures)
Because vitamin K is involved in several aspects of bone health - carboxylation of bone-related proteins, genetic transcription of osteoblastic markers, regulating bone reabsorption.
Insufficient intake can interfere with these processes, reduce bone mineral density, and increase the risk of bone fractures and osteoporosis 18.
Contact your healthcare professional immediately if you’re experiencing any of these symptoms. A vitamin K deficiency isn’t something you want to play around with and can lead to severe consequences if left unchecked.
Where To Find Vitamin K (+ The Best Vitamin K Supplements)
So, how do you get enough vitamin K?
Boosting your vitamin K intake through diet is easy, as it’s available in several delicious and highly nutrient-dense food sources:
- Vitamin K1: Kale, collard greens, turnip greens, spinach, broccoli, Brussel sprouts, and other green leafy vegetables
- Vitamin K2: Natto, cheese curds, hard cheeses, chicken, egg yolks, sauerkraut, butter, beef liver
Alternatively, vitamin K supplements are one of the best ways to ensure you avoid a vitamin K deficiency.
And for us, supplementation is a must to ensure you’re meeting your intake requirements for both vitamin K1 and vitamin K2 to avoid vitamin K deficiency bleeding - but not just any old vitamin K supplement. Performance Lab NutriGenesis Multi is the best way to fulfill your vitamin K needs.
And because vitamin K is often supplemented alongside vitamin D, you’re getting a good dose of D, too. NutriGenesis Multi provides only the cleanest, purest, and most effective forms of all nutrients for maximum absorption and activity. Plus, it supplies 100% RDI of 17+ essential vitamins and minerals for optimal performance body-wide.
