Has your mind jumped to leafy greens and their role in blood clotting? Good thing I caught you. You are thinking of Vitamin K1. This article is devoted to Vitamin K2, it’s fat-soluble cousin. K1 and K2 were thought to be different forms of the same vitamin until the late 1990s. Now we know that K2 is very different from K1: it is found mostly in animal-derived food sources as well as some fermented foods. The list of its health promoting effects is long and impressive.