Which Disease is Caused by Deficiency of Vitamin K2? Understanding the Risks to Bone and Heart Health

November 1, 2025 •

5 min read

While many associate vitamin K with blood clotting, a deficiency of its lesser-known cousin, vitamin K2, is linked to a range of severe and often overlooked diseases. For instance, certain studies show that a diet high in vitamin K2 can significantly reduce the risk of coronary heart disease. A primary function of this nutrient is to properly regulate calcium, and its deficiency impacts both bone density and cardiovascular health.

Quick Summary

A shortage of vitamin K2 can lead to conditions like osteoporosis due to impaired bone mineralization and contribute to vascular calcification, increasing the risk of heart disease. It disrupts the body's ability to direct calcium to the right places, impacting both skeletal and cardiovascular systems.

Key Points

Osteoporosis and Fractures: A vitamin K2 deficiency impairs the activation of osteocalcin, a protein essential for binding calcium to bones, leading to weakened bones and a higher risk of fractures.
Vascular Calcification and Heart Disease: Without sufficient vitamin K2, Matrix Gla Protein (MGP) remains inactive, allowing calcium to deposit in artery walls, which can cause arterial stiffness and increase the risk of heart disease.
Poor Dietary Intake: Modern Western diets often lack sufficient sources of vitamin K2, such as fermented foods and organ meats, contributing to widespread deficiency.
Fat Malabsorption: Since vitamin K2 is fat-soluble, conditions that hinder fat absorption, like celiac disease or cystic fibrosis, significantly increase the risk of deficiency.
Newborn Bleeding (VKDB): Newborns are particularly vulnerable to a serious bleeding disorder due to low vitamin K stores at birth, making routine vitamin K injections standard practice.
Different Functions of K1 vs. K2: While K1 from leafy greens is crucial for blood clotting, K2 plays a distinct role in regulating calcium distribution for bone and cardiovascular health.

The Critical Role of Vitamin K2

Vitamin K is not a single compound but a group of fat-soluble vitamins. It exists in two primary forms: vitamin K1 (phylloquinone), mainly found in leafy greens and essential for blood clotting, and vitamin K2 (menaquinone), found in animal products and fermented foods, with crucial extrahepatic functions. K2 is primarily responsible for regulating how the body uses calcium beyond blood coagulation. Its deficiency, therefore, leads to a different set of problems than a general lack of vitamin K1. These issues stem from the body's inability to properly activate key proteins that manage calcium throughout the body.

Which diseases are caused by deficiency of vitamin K2?

A deficiency in vitamin K2 can manifest in serious chronic health issues, particularly affecting the skeletal and cardiovascular systems, as the body struggles to manage calcium effectively without this vital nutrient.

Osteoporosis: Vitamin K2 activates osteocalcin, a protein produced by osteoblasts (bone-building cells). Functional osteocalcin binds calcium to the bone matrix, promoting proper mineralization. Without sufficient K2, osteocalcin remains inactive, leading to low bone mineral density (osteopenia) and eventually osteoporosis, characterized by weak and brittle bones susceptible to fracture. In fact, some studies in Asian populations have explored K2 supplementation as a treatment for osteoporosis.
Cardiovascular Disease: Vitamin K2 deficiency contributes significantly to vascular calcification, a major risk factor for heart disease. The nutrient activates another crucial protein, Matrix Gla Protein (MGP), which acts as a powerful inhibitor of calcification in soft tissues like the arteries. When K2 levels are low, MGP becomes inactive, allowing calcium to accumulate in artery walls. This process leads to arterial stiffening, atherosclerosis, and an increased risk of heart attacks and strokes.
Dental Health Issues: Following the same mechanism as bone health, vitamin K2 influences the calcification of teeth by activating osteocalcin, which supports the growth of new dentin. A deficiency can, therefore, lead to weakened teeth and an increased risk of periodontal disease over time.

How does vitamin K2 compare to vitamin K1?

While both are forms of vitamin K, their functions and sources differ significantly. Understanding these differences is key to ensuring adequate intake for overall health.


Feature	Vitamin K1 (Phylloquinone)	Vitamin K2 (Menaquinone)
Primary Function	Activating hepatic clotting factors for blood coagulation.	Activating proteins that regulate calcium, primarily affecting bone and heart health.
Dietary Sources	Found mainly in leafy green vegetables, such as kale, spinach, and broccoli.	Found in fermented foods like natto, some cheeses, and animal products like egg yolks and liver.
Bodily Action	Mostly utilized by the liver for blood clotting processes.	Plays a more prominent extrahepatic role, particularly in bones and arterial walls.
Half-Life	Has a shorter half-life in the body.	Has a longer half-life, making it more readily available for extrahepatic tissues.
Endogenous Synthesis	Not produced by the body.	Synthesized in small quantities by gut bacteria, but typically insufficient to meet needs.

Causes and risk factors for K2 deficiency

Vitamin K2 deficiency is more common than many people realize, particularly in Western diets. While it's rare for a healthy adult to develop a vitamin K deficiency based purely on diet, certain factors increase risk.

Poor Dietary Habits: A modern Western diet, which often lacks fermented foods and organ meats, is a major contributing factor. Many people rely on K1-rich vegetables but miss out on the K2 from other sources. Furthermore, a very low-fat diet can hinder the absorption of fat-soluble vitamins like K2.
Gastrointestinal Disorders: Conditions that affect fat absorption can impede the body's ability to absorb vitamin K2 from food. This includes celiac disease, cystic fibrosis, Crohn's disease, and chronic pancreatitis.
Medication Use: Long-term use of certain medications, such as some antibiotics, can disrupt the gut bacteria that produce a small amount of K2. Blood-thinning drugs like warfarin are specifically designed to interfere with vitamin K metabolism.
Liver Disease: Since the liver is involved in vitamin K metabolism, significant liver disease can increase the risk of deficiency and bleeding problems.
Newborns: Infants are particularly susceptible to vitamin K deficiency bleeding (VKDB) because of low placental transfer of vitamin K and a sterile gut at birth. This is why a vitamin K injection is standard practice for newborns.

Preventing K2 deficiency through diet

Prevention of K2 deficiency centers on incorporating a variety of nutrient-rich foods into your diet. While supplements are an option, especially for those with risk factors, obtaining K2 from natural food sources is an excellent strategy.

Here are some of the best dietary sources of vitamin K2:

Natto: A traditional Japanese dish of fermented soybeans, natto is exceptionally rich in K2, particularly the highly bioavailable MK-7 form.
Hard and Soft Cheeses: Certain aged and fermented cheeses, such as Gouda and Brie, are good sources of K2.
Egg Yolks: Eggs, especially from free-range chickens, contain vitamin K2 in the MK-4 form.
Liver and Organ Meats: Beef and chicken liver are significant sources of MK-4, a form of K2 that is synthesized from K1 in animal tissues.
Grass-Fed Dairy: Butter and full-fat milk from grass-fed cows can contain higher levels of K2.

Conclusion

While a vitamin K deficiency is often associated with bleeding disorders, particularly in infants, understanding which disease is caused by deficiency of vitamin K2 reveals a broader spectrum of chronic health risks. Insufficient K2 compromises the body's ability to manage calcium, leading to poor bone mineralization, which can result in osteoporosis, and the dangerous accumulation of calcium in arterial walls, increasing the risk of cardiovascular disease. By incorporating more K2-rich foods into a balanced diet, such as natto, certain cheeses, and egg yolks, and being mindful of risk factors like specific medications or malabsorption disorders, individuals can take proactive steps to safeguard their skeletal and cardiovascular health. Consulting with a healthcare professional can provide personalized guidance on prevention and management, especially for those with existing health conditions or specific dietary needs.

For more detailed information, consult the National Institutes of Health (NIH) Office of Dietary Supplements website.

Note: This is not medical advice. Individuals with specific health concerns should consult a healthcare provider.

Frequently Asked Questions

Vitamin K2's primary functions are to activate specific proteins, like osteocalcin for bone mineralization and Matrix Gla Protein (MGP) to prevent calcium accumulation in soft tissues like arteries. It helps direct calcium to the bones and teeth, where it is needed, while keeping it out of blood vessels.

Diagnosing a vitamin K2 deficiency can be challenging, as it often doesn't show up in routine blood clotting tests. Symptoms may be subtle and include easy bruising or excessive bleeding in severe cases, but the long-term consequences are more insidious, such as weakened bones (osteoporosis) and cardiovascular issues from vascular calcification.

While severe vitamin K deficiency causing bleeding is rare in healthy adults, a suboptimal intake of vitamin K2 leading to long-term health issues like poor bone and cardiovascular health may be more common, particularly in populations consuming Western diets low in fermented foods and organ meats.

The richest source of vitamin K2 (MK-7) is natto, a Japanese fermented soybean product. Other sources include certain cheeses (Gouda, Brie), egg yolks, liver, and some animal products, especially from grass-fed animals.

Vitamin K1 is mainly responsible for activating clotting factors in the liver, while vitamin K2 has a more widespread extrahepatic function. K2 is crucial for bone and heart health by ensuring calcium is deposited correctly in the body's tissues.

Newborns have very low vitamin K reserves because little of it crosses the placenta. Their gut flora also isn't developed enough to produce K2. A vitamin K shot at birth is standard practice to prevent Vitamin K Deficiency Bleeding (VKDB), a potentially fatal bleeding disorder.

Yes, certain medications can interfere with vitamin K2 absorption or metabolism. Long-term use of antibiotics can destroy gut bacteria that produce K2, and blood-thinning medications like warfarin intentionally block the action of all forms of vitamin K.