Here is a very comprehensive article on the many benefits of vitamin K2. I admit that it may sound too good to be true, and that Life Extension tends toward a bias in favor of vitamins in general. But at the end of the article, on page 3, there are numerous references.
www.lef.org/magazine/mag2009/jan2009_Vitamin-K-Protection-Against-Arterial-Calcification-Bone-Loss-Cancer-Aging_01.htm