Vitamin K
Vitamin K is a fat soluble vitamin found in two forms. Both are used to attach calcium to certain proteins, to make them functional.
Also used to control glutamate receptors (Glutamate opens up calcium ion channels, which are responsible for turning on lots of processes in the body. Magnesium and taurine help close those channels.)
K1: Leafy greens, brussel sprouts, broccoli, asparagus
Phylloquinone used mostly for blood clotting
K2: Yellow grassfed butter, pastured eggs, fish roe, natto
Menaquinone used mostly for healthy bones and teeth
The fact is, for a healthy person not on medications, adequate vitamin K2 is easy to get from the Primal eating plan. Although an RDA for K2 hasn’t been established, Dietary Reference Intakes for vitamin K1 suggest between 90-120 µg/day. (I’ll be on the lookout for updates on K2 doses, but I’ll note that toxicity doesn’t appear to be a problem with vitamin K, and no UL (Tolerable Upper Intake Level) has been established.)
Deficiency
A deficiency of vitamin K (found in dark green, leafy vegetables) also can cause you to bruise easily. You're most likely to run low on vitamin K if you've been taking antibiotics that destroy vitamin K-synthesizing microorganisms in the digestive tract.