Low levels of Vitamin K and D have been associated with a higher risk of cardiovascular disease including hardening of the arteries. Specifically, vitamin K deficiency has been linked to age-associated conditions including bone fragility after estrogen loss, (osteocalcin) and arterial calcification, (hardening of arteries) a predictor of cardiovascular disease. In fact, a recent study found that supplementation with vitamin K significantly slowed the natural progression of coronary artery calcification. While it’s too soon to say that by taking Vitamin K and D supplements you will prevent hardening of the arteries, it’s not too soon to say you should make sure you are getting enough of both these important vitamins for many health reasons - including hedging your bets against cardiovascular disease and others. The best way to ensure you meet the proper levels (vitamin K ~110 mcgs/day; vitamin D ~1000 IU/day) is to eat the best you can, including green leafy vegetables and take a daily multivitamin and mineral formula containing 600-1000 IU of D and 50 mcgs of K. If you are on blood thinning medication (e.g. warfarin, etc.) check with your doctor regarding taking any supplement containing Vitamin K.