The term vitamin K represents a collection of fat-soluble substances that all possess hemostatic activity. Vitamin K includes: K1, or phylloquinone which is found in green leafy vegetables; K2, or menaquinones, which are in egg yolk, butter, cow liver and cheeses; K3, menadione; and K4, which is a salt of K3 that is water-soluble. K4 can be converted into K3. Vitamin K is involved in bone metabolism, has the ability to hunt down reactive oxygen species, and can hinder lipid peroxidation. There is evidence that vitamin K may also possess anticarcinogenic abilities. Vitamin K deficiencies are uncommon although it is important to make sure your body has the proper amounts.
Vitamin K should not be combined with warfarin due to decreased effectiveness of the anticoagulant. This diminished anticoagulant effect may be added to when vitamin K is combined with CoQ10, vitamin A, and vitamin E; these combinations should be avoided.
At the time, supplemental vitamin K has no reported side effects.
View Research related to Vitamin K1.