Nutrients from A to Z: Vitamin K – The Calcium Traffic Cop Your Bones and Arteries Need

So, you know about calcium and vitamin D: but have you ever heard of the vitamin that helps tell your body where calcium should go?

Most people haven’t. Yet vitamin K may be an important part of the bone health and vascular health story. Think of it as the calcium traffic cop: helping direct calcium into places that need it, such as your bones and teeth, while supporting healthy function in soft tissues.

Let’s talk about vitamin K.

Today’s roadmap

Today we’re diving into the two major forms of vitamin K, why K2: especially MK-7: is getting so much attention, the check-engine signals your body may be sending, and how food, gut health, fat absorption, and functional testing all fit together.

We’ll also cover an important safety note for anyone taking blood-thinning medication.

What is vitamin K?

Vitamin K is a fat-soluble nutrient involved in normal blood clotting and the activation of several proteins throughout the body.

Here’s the simple analogy: imagine calcium as a fleet of delivery trucks. Calcium is valuable, but it needs directions. Vitamin K helps activate the proteins that guide those calcium trucks toward bone and away from places where unwanted calcium accumulation may affect healthy tissue function.

That’s why I like to call vitamin K the calcium traffic cop.

Vitamin K does not work alone. Calcium does not work alone. Vitamin D does not work alone. Your body operates as a connected system, and nutrients often work together in pathways rather than acting like isolated switches.

The two forms: K1 and K2

The first major form is vitamin K1, also called phylloquinone.

K1 is found primarily in green leafy vegetables and some plant oils. It is the main dietary form of vitamin K for many people and plays an important role in supporting normal blood clotting through vitamin K-dependent proteins made in the liver.

The second family is vitamin K2, known as the menaquinones.

K2 includes several forms, including MK-4 and MK-7. These forms are found in fermented foods and certain animal foods. Some K2 is also produced by bacteria in the digestive tract, although the amount produced and how much is available to the body can vary.

MK-7, or menaquinone-7, is a longer-chain form of K2. It has a longer half-life in the body than K1, meaning it remains available for a longer period. This has made MK-7 particularly interesting when researchers look at vitamin K-dependent proteins outside the liver, including proteins involved in bone and vascular tissue.

One of those proteins is osteocalcin. Osteocalcin is produced by bone-forming cells and helps bind calcium within the bone matrix when it is properly activated.

Another is matrix Gla protein, or MGP. MGP is found in tissues including blood vessels and cartilage. When properly activated, it supports the body’s natural systems for managing calcium in those tissues.

Vitamin K acts as a cofactor in a process called carboxylation. In plain language, it helps switch these proteins into a functional form so they can do their jobs.

That’s the calcium traffic-cop mechanism.

What are the check-engine signals?

Before we go any further, these signs are not a diagnosis of vitamin K insufficiency. They are simply signals worth discussing with a qualified health professional, especially if they are persistent or unexplained.

Some signals may include:

• Easy bruising
• Bleeding gums
• Heavier-than-usual menstrual bleeding
• A history of low bone density or osteopenia
• A family history of osteoporosis
• Concerns about vascular stiffness or calcification
• A diet consistently low in leafy greens and other nutrient-dense foods
• Digestive issues that affect fat absorption
• Recent or prolonged use of certain antibiotics
• The use of blood-thinning medication

Vitamin K is fat-soluble, so the ability to digest and absorb dietary fat matters. Conditions affecting bile flow, pancreatic function, or intestinal absorption may influence the body’s ability to use fat-soluble nutrients.

And here is the critical safety warning:

If you take warfarin, also known as Coumadin, you must talk with your prescribing doctor before changing your vitamin K intake or beginning a vitamin K supplement.

Do not suddenly add a high-dose K1 or K2 product on your own. Vitamin K can interact with warfarin and affect anticoagulation. The goal is usually consistency and appropriate monitoring: not making abrupt changes. Your doctor may advise you about the right amount of vitamin K for your individual situation and may monitor your INR.

We don’t guess: we test

In functional medicine, we don’t want to assume that a symptom tells the whole story. We look at patterns and, when appropriate, we test.

Standard clinical vitamin K deficiency is considered uncommon in healthy adults. However, that does not necessarily mean every person has optimal vitamin K activity in every tissue.

Some specialized assessments look at functional markers such as:

• Undercarboxylated osteocalcin, sometimes used to explore vitamin K activity related to bone
• Dephosphorylated-uncarboxylated MGP, or dp-ucMGP, a marker researchers use when evaluating vitamin K activity related to vascular tissue
• Standard blood chemistry, digestive health markers, and nutrient patterns
• Relevant medication history and dietary intake

These markers are not something everyone needs routinely. They need to be interpreted in context by a qualified clinician.

Remember, vitamin D helps the body absorb and regulate calcium, while vitamin K helps activate proteins involved in calcium placement and use. You can think of vitamin D as helping make calcium available and vitamin K as helping with the directions.

That does not mean more is always better. It means the entire nutrient network matters.

Where do you get vitamin K?

Food comes first.

For vitamin K1, look to:

• Kale
• Spinach
• Collard greens
• Broccoli
• Brussels sprouts
• Parsley
• Romaine lettuce
• Other dark leafy greens

For vitamin K2, food sources include:

• Natto, a fermented soybean food and one of the richest dietary sources of K2
• Fermented foods
• Egg yolks
• Cheese
• Grass-fed butter
• Organ meats
• Dark-meat poultry

Natto is not a familiar food for everyone, but it is an excellent example of how fermentation can change a food’s nutrient profile.

And this is where two principles fit beautifully: “As is your food, so is your mind,” and “You are what you eat.”

Those phrases are not meant to create fear around food. They are reminders that what we eat supplies the raw materials for energy production, neurotransmitter balance, tissue maintenance, digestion, and overall wellness. A plate built around colorful plants, quality protein, healthy fats, and appropriately prepared foods can support both physical and mental function.

Before you run to the supplement aisle, look at your plate. Then look at your digestion. Then consider whether your eating pattern is consistent enough to support your needs.

The supplement aisle can be considered second, and only with appropriate guidance. Designs for Health offers vitamin K2 products featuring MK-7, including K2 Supreme. A supplement may be appropriate for some people, but product selection, dosage, medication interactions, and your individual health history all matter.

A supplement should complement a health plan: not replace a nourishing diet or professional guidance.

Sometimes the food isn’t the problem: it’s the factory

Your digestive tract is more than a passageway for food. It is part of a highly active biological factory.

Gut bacteria can produce certain forms of vitamin K2, although the amount and availability may vary from person to person. Antibiotic exposure, poor dietary variety, digestive imbalance, and other gut health challenges may influence this internal ecosystem.

Fat absorption also matters because vitamin K is fat-soluble.

That means eating a salad by itself may not be the same as eating those greens with a source of healthy fat. Try pairing leafy greens with olive oil, avocado, eggs, nuts, seeds, or another food that works well for your dietary needs. Some people may also enjoy greens with a small amount of butter.

The point is not to add unlimited fat. The point is to remember that nutrients need the right environment to be absorbed and used.

Vitamin K and whole-body health

Vitamin K is a reminder that everything in your body is connected.

Calcium does not work alone. Vitamins do not work alone. Your digestive system, bones, blood vessels, muscles, nervous system, and spine do not operate as separate departments.

That is also why our approach at Carlucci Chiropractic & Wellness looks beyond a single symptom. Chiropractic care, nutrition, functional wellness, movement, and personalized home strategies can all be pieces of a larger health picture.

The spine is part of a living nervous system. The nervous system communicates with the body. The body depends on nutrients, circulation, movement, and recovery. Whole-body health means paying attention to those connections.

If you are in the Montclair area and want to learn more about your individual health patterns, click the Linktree in our bio or visit the booking page to schedule a consultation. You can also learn more about our services and our Montclair location.

And don’t forget to like this video if you learned something new today, and subscribe for more deep dives into the science of wellness. You can find the companion YouTube video here: Vitamin K long-form video.

I’m Dr. Kim Carlucci, and I’ll see you in that next video. Have a great day.

Medical Disclaimer: These statements have not been evaluated by the FDA. This content is for educational purposes only and not intended as medical advice.

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