HI Meredith,
Vitamin K is the one that is needed for blood clotting.And,it is necessary for bones to form. It also is important in the liver--it helps convert glucose to glycogen that is stored in the liver.Most of this vitamin in made in your intestines by the friendly bacteria present.

It is found in green leafy veggies, eggs,oatmeal products, wheat product and there is a long list.

This vit can accumulate if taken in large doses and produce sweating, flushing and blood clots.I met a guy in the barber shop several months ago that had to have his blood tested weekly because his Vit K level was too high. I had never heard of that but he said the Docs were concern about strokes.
God Bless---Harry