Should You Supplement with Vitamin K2?
Vitamin K is an essential nutrient known primarily for its role in blood clotting. However, it also plays a critical part in bone health, brain health, cardiovascular health, and proper calcium metabolism. While many people are familiar with vitamin K1, vitamin K2 has gained attention for its unique benefits, and for the question of whether supplementation might be necessary.
Understanding Vitamin K: The difference between k1 and k2
Vitamin K exists in two main forms:
Vitamin K1 (Phylloquinone)
Found primarily in green leafy vegetables like spinach, kale, and broccoli.
Plays a central role in blood clotting.
Typically sufficient in a balanced diet with plenty of vegetables.
Vitamin K2 (Menaquinone)
Found in fermented foods like natto, certain cheeses, and some animal products such as egg yolks and liver.
Plays a key role in bone and cardiovascular health by directing calcium to the bones and teeth rather than soft tissues and arteries.
Produced in small amounts by gut bacteria, but dietary intake is often low in many populations.
Unlike K1, which is mostly involved in clotting, K2 is especially important for calcium regulation, which may influence bone strength and cardiovascular health.
Potential Benefits of Vitamin K2
1. Bone Health
Vitamin K2 activates osteocalcin, a protein that helps bind calcium into bone tissue. Some studies suggest that adequate K2 intake may reduce the risk of osteoporosis and improve bone mineral density, particularly in postmenopausal women.
2. Cardiovascular Health
K2 helps activate matrix Gla protein (MGP), which inhibits calcium buildup in blood vessels. This process may support arterial flexibility and reduce the risk of vascular calcification (hardening of arteries).
3. Synergy with Vitamin D and Calcium
K2 works synergistically with vitamin D and calcium to ensure that calcium is deposited where it is needed (bones) and not in soft tissues or arteries. This makes it a potentially valuable supplement for people taking vitamin D or calcium supplements.
Do You Need to Supplement with K2?
Vitamin K1 can convert to K2 (MK-4) in the body, but tends to do so inefficiently. Generally, we cannot rely on this conversion alone for bone and cardiovascular health.
Vitamin K2 supplementation may be considered in certain situations:
Limited dietary intake of fermented foods (natto, sauerkraut, tempeh) or animal sources (egg yolks, some high fat dairy) rich in K2.
Individuals at risk for osteoporosis, particularly postmenopausal women or older adults.
People taking long-term vitamin D supplements, since adequate K2 helps direct calcium to bones.
Those concerned with cardiovascular health and arterial calcification, especially if other risk factors are present.
Dosage and Forms
Vitamin K2 is available in two main forms:
MK-4 – Shorter-chain menaquinone, often requires multiple daily doses.
MK-7 – Longer-chain menaquinone, more bioavailable, and typically taken once daily.
Common supplemental dosages range from 50–200 mcg per day, particularly for MK-7, though the optimal dose can depend on age, diet, and health status.
Safety Considerations
Vitamin K2 supplementation is generally considered safe for healthy individuals. However:
People on blood-thinning medications (such as warfarin) should consult their doctor before supplementing, as vitamin K can affect anticoagulant activity.
High doses are usually not necessary for most healthy adults.
Bottom Line
Vitamin K2 plays a unique and important role in bone and cardiovascular health, distinct from the blood-clotting functions of K1. While many people get sufficient K1 through green vegetables, K2 intake is often lower, especially in Western diets that include fewer fermented foods.
Supplementation with K2 may be particularly beneficial for older adults, postmenopausal women, those taking vitamin D, or individuals at risk of osteoporosis or vascular calcification. As always, it’s best to discuss supplementation with a qualified healthcare professional to ensure the right form and dosage for your individual needs.
Courtney Rae Jones is a Registered Holistic Nutritionist. She is also a Culinary Nutrition Expert having completed her certification in alternative & specialized diets through the Academy of Culinary Nutrition. She specializes in digestive health and balancing women’s reproductive hormones. To work with Courtney, please contact us.