The levels of vitamin K in healthy menopausal women are inadequate to maintain bone health, says the lead researcher of a recent study from the University of Michigan School of Nursing. The researchers found that one early effect of declining estrogen is the impairment of vitamin K function, and that the deficiency could seriously compromise bone health and contribute to the development of osteoporosis.

While vitamin K comes from green leafy vegetables and vegetable oils, most individuals don’t consume sufficient dietary amounts to promote proper bone health. Vitamin K is essential for making a fully functional bone protein called osteocalcin. With adequate vitamin K, this protein can bind like glue to calcium in the bone environment.

In related news from the University of York in England, researchers conducted a review of clinical trials to assess whether vitamin K supplementation can actually reduce bone loss and prevent fractures. An extensive search of medical databases back to 1945 provided 20 randomized, controlled clinical trials that involved vitamin K supplementation (13 trials were on bone loss, and 7 were on bone fractures). The researchers found that all studies but one reported reduced bone loss due to vitamin K supplementation.

Vitamin K is available as a stand-alone supplement, and is also included in some calcium and multivitamin formulations.

Sources: Arch Intern Med. 2006 Jun 26;166(12):1256-61; Menopause. 2006 Sept/Oct;13(5)