Vitamin K2 is a fat soluble vitamin K analouge that plays a role in bone metabolism. Vitamin K2 is also known as menaquinone. Vitamin K2 can exist in many forms in natural, but the two most common are menaquinone 4 (MK4) and and menaquinone 7 MK7 form.
Vitamin K2 as MK4 is synthesized by animal tissues and is found in eggs, meat and dairy products. Vitamin K2 as MK7 is synthesised by bacterial fermentation and MK7 is found in fermented foods such as natto.
MK4 Vitamin K2 has been shown specifically to prevent bone lose and increased fracture risk from corticosteriod use, anorexia and general disuse (leading to weaker, less dense bone tissue). Vitamin K2 plays a key role in activating certain proteins that control calcium metabolism within the body and particularly mineraliation of bone.