Vitamin K

What is it?

Vitamin K is a fat soluble nutrient needed for blood clotting and bone health.

Function How it helps
Blood clotting

It used in the liver to form thrombin and for the conversion of fibrinogen into fibrin. It is also needed to manufacture other blood clotting compounds needed to coagulate and clot blood, preventing excess blood loss.

Bone health Needed for the process of binding calcium to the bone matrix.


What is it used for?
General bone health Osteoporosis
Excessive bleeding Excessive menstrual bleeding

Preventing haemorrhage in new-borns


Best food sources

Dark green leafy vegetables



Green tea





Egg yolks

Brussel sprouts Olive oil Vegetable oils


Deficiency Symptoms

Intra-cranial haemorrhage in newborns

Excessive bleeding

Weak bone density


Easy bruising

Supplementation dosage range

100-500ug per day

Other information

Vitamin K is sometimes used in conditions where there are absorption problems or excess bleeding.


  • Vitamin K1 is not associated with toxicity at supplemental dosages.

  • In pregnancy or when breast feeding vitamin K supplementation should only be used under medical supervision.
  • Vitamin K supplementation should only be used under strict medical supervision if taking anticoagulant drugs such as warfarin, heparin, aspirin, as it may counteract the drugs’ effect. Vitamin K may also counteract the anti-coagulant effects of certain nutrients and herbs such as high-dose vitamin E, omega 3 fats, garlic.
  • Unless under strict medical supervision, vitamin K supplementation (all forms) should not be taken with the anti-malarial/anti-protozoal drug primaquine, as this nutrient may increase the drug’s toxic side effects.


Factors which deplete levels, impair absorption and/or inhibit activity:

Anti-coagulant drugs (warfarin, heparin, aspirin)

Fat blocking agents

Cholesterol/lipid lowering drugs


Mineral oil

Mineral oil





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