Vitamin K1 vs K2: a side-by-side comparison

Name

Phylloquinone (single substance)

Menaquinone (a family of similar molecules called MK, from MK-4 to MK-13. MK-4 is the type most often consumed in food.)

What does it do?

Blood clotting - prevents excessive bleeding. (K1 is what prevents a paper cut from becoming dangerous.) 

• Helps direct calcium to the right places (into bones and teeth and out of soft issues like arteries and kidneys)

• May help support bone, heart and brain health.

Found in

Green leafy vegetables

• Fermented foods (some European hard cheeses and Natto or fermented soybeans)

• Fatty organ meats like liver

• Chicken dark meat

• Some pork products

• Egg yolks from pastured chicken

• Grass-fed butter

Contained in multivitamins?

Yes

No

Fat-soluble

Yes, best if eaten with some fat

Yes, best if eaten with some fat

Deficiency

Rare, except in newborns.

Common

Daily Value (RDA)

90 micrograms for women

120 micrograms for men

Not yet established, but experts recommend 100 to 200 micrograms of K2 daily.

Toxicity

No known toxicity if taken at recommended levels.

No known toxicity if taken at recommended levels.

Deficiency symptoms

• Bruises
• Increased bleeding time
• Small blood clots under nails
• Increased bleeding in mucous membranes.

• Weak bones
• Increased plaque deposits along gumline
• Increase in cavities
• Arterial calcification

Causes of deficiency

• Lack of green leafy vegetables in diet
• Anticoagulant medications (Warfarin/Coumadin)
• Antibiotics
• Fat malabsorption disorders.

Lack of fermented foods and organ meats in diet.

Circulation in blood

Prolonged (days).

Due to Vitamin K2's longer molecule, it is transported by different carriers in the blood than K1 and therefore, to different locations in the body. 

Effect on bone health

Minimal

Moderate

Effect on heart health

Present in brain

Yes.

The MK-4 form of Vitamin K2 is the predominant form found in the brain, but we don't yet know what it does there. 

What happens after consumption?

• Vitamin K1 travels to liver more effectively than to bones.
• Liver uses Vitamin K1 to activate proteins needed for blood clotting.

• Vitamin K2 travels to bone more effectively than K1.
• Bones use K2 to produce Osteocalcin, a bone-building protein hormone, which also supports metabolic health.
• The MK-4 form of Vitamin K2 is effective at reaching tissues other than liver and bones.
• The MK-7 form of K2 is 3X better at reaching bones and activating Osteocalcin than K1. 

Effect on gene expression

No known influence on gene expression.

MK-4 form of Vitamin K2 shows some influence on gene expression.

Interferes with function of blood thinning medications

Yes. Anti-coagulant medications work by creating an artificial Vitamin K deficiency. 

Yes. Vitamin K2 can also interfere with the blood thinning medications. Talk to your doctor before using Vitamin K2 supplements if you are taking Warfarin or other similar drugs. 

Dietary contribution to Vitamin K activity

Major. Close to 90% of Vitamin K in western diets is from Vitamin K1. 

K2 as MK-4: minor as a direct dietary source of Vitamin K.

K2 as MK-7: minor as a direct dietary source of Vitamin K

As MK-10 to MK-13: minor.