Vitamin K and Bone Turnover in Postmenopausal Women

This one year study of the K vitamers phylloquinone (K1) and menatetranone (MK4) will study supplementation effects on bone turnover and bone density. Women at least 5 years postmenopause with normal bone density who do not use estrogen therapy or the following medications may be eligible: alendronate (Fosamax), risedronate (Actonel), pamidronate (Aredia), etidronate (Didronel), zoledronate (Zometa), teriparatide (Forteo), raloxifene (Evista), tamoxifene, warfarin (Coumadin), anti-seizure medications, prednisone, or oral steroids. Eligible subjects will take calcium and vitamin D (Citracal) twice a day for the first two months and through-out the study. After the first two months, subjects are randomized to the K1, MK4 or placebo groups. Return visits occur at 1, 3, 6 and 12 months. Fasting blood and urine is collected at each visit and bone density is performed at 3 study visits.

Female, 5 years postmenopause. Ambulatory. Community dwelling. Able to ingest calcium and vitamin D supplements. Willing to restrict vitamin K intake. Stable thyroid dose if appropriate. No history of hyperthyroidism, hyperparathyroidism or other metabolic bone diseases. Absence of hardware in hip and spine. History of malignancy within the last five years. Not currently using coumadin or warfarin. Vitamin D supplements must be less than 800 IU daily. Have not used estrogen or other bone-altering medications (see list in study description) within the last year. No history of liver disease or malabsorption. No known allergy to vitamin K. Have not participated in an investigational drug trial within the last month.

Kumar R, Binkley N, Vella A. Effect of phylloquinone supplementation on glucose homeostasis in humans. Am J Clin Nutr. 2010 Dec;92(6):1528-32. doi: 10.3945/ajcn.2010.30108. Epub 2010 Sep 29.