Vitamin K2

What is Vitamin K2?

Vitamin K2, also known as menaquinone, is a fat-soluble vitamin that plays a crucial role in calcium metabolism in the body. It is part of the vitamin K family, which also includes K1 (phylloquinone). Vitamin K2 is particularly important for directing where calcium should go in the body, meaning it helps channel calcium to bones and teeth instead of accumulating in blood vessels.

How does it work in the body?

Vitamin K2 activates proteins involved in calcium metabolism, such as osteocalcin and matrix Gla-protein (MGP). Osteocalcin helps bind calcium in the bone, strengthening bone structure, while MGP prevents calcium deposits in blood vessels. This makes vitamin K2 synergistic with vitamin D3, which is also important for calcium absorption in the intestine.

Scientific benefits

Several studies have demonstrated the positive effects of vitamin K2 on health:

• Bone health: A study published in Osteoporosis International showed that supplementation with vitamin K2 can increase bone mass and reduce fracture risk in elderly women.
• Heart health: Research in the Journal of Thrombosis and Haemostasis showed that higher intake of vitamin K2 was associated with a lower risk of cardiovascular diseases by reducing calcium deposits in blood vessels.
• Insulin resistance: A study published in Diabetes Care showed that vitamin K2 can improve insulin sensitivity, which is important for preventing type 2 diabetes.

Dosage and recommendations

There is no official recommended daily dose for vitamin K2, but many experts suggest an intake between 90–120 micrograms per day for adults. It is important to consult a doctor or dietitian before starting supplementation, especially if taking anticoagulants such as warfarin, as vitamin K can affect the medication's efficacy.

Best sources and forms

Vitamin K2 is found in various foods and can also be taken as a dietary supplement. Some of the best sources include:

• Fermented foods such as natto (fermented soybeans)
• Dairy products, especially cheese
• Meat, particularly organ meats like liver
• Eggs
• Green leafy vegetables, although these primarily contain K1

Vitamin K2 exists in different forms, with MK-4 and MK-7 being the most studied. MK-7 has a longer half-life in the body, which may make it more effective as a supplement.

Side effects and warnings

Vitamin K2 is generally considered safe, but it is important to be aware of the following:

• Individuals taking anticoagulants should exercise caution and always consult their doctor before starting vitamin K2 supplements.
• Excessive consumption of K2 through supplements may potentially lead to adverse effects, but there are few documented cases of toxic overdose.

Frequently asked questions

What is the difference between vitamin K1 and K2?

Vitamin K1 is mainly found in green leafy vegetables and is important for blood coagulation, whereas vitamin K2, found in fermented foods and animal products, is crucial for calcium metabolism and bone health.

How can I get enough vitamin K2?

You can increase your intake of vitamin K2 by including foods such as natto, cheese, eggs, and certain meat products in your diet. Supplements may also be considered if you have difficulty obtaining sufficient amounts through diet.

Is vitamin K2 good for the heart?

Yes, research suggests that vitamin K2 may help reduce the risk of cardiovascular diseases by preventing calcium deposits in blood vessels.

Can I take vitamin K2 together with vitamin D3?

Yes, vitamin K2 and D3 work synergistically in the body and can together support bone health and calcium metabolism.

Do I need to take vitamin K2 as a supplement?

It depends on your diet and individual health needs. If you have a diet rich in K2 sources, supplements may be unnecessary, but individuals with limited diets might consider taking it.