An avalanche of favorable studies has resulted in record numbers of Americans supplementing with vitamin D. Since it is virtually impossible to obtain adequate vitamin D from food sources, supplementation with 5,000-8,000 IU daily is required by many aging individuals. Overlooked by almost everyone (except Life Extension members) is the critical importance of vitamin K. If one is concerned enough about their health to take higher dose vitamin D, it seems absurd to miss out on the benefits of vitamin K. For instance, vitamin D facilitates calcium absorption into the bloodstream and thus plays an important role in maintaining bone density. Less recognized is the need for vitamin K to transport calcium from the bloodstream into the bone. Vitamin K is also required by calcium-regulating proteins in the arteries. Together these two vitamins help maintain youthful calcium skeletal distribution while promoting vascular health.