In September of 2008, I attended the large American Society for Bone Mineral Research Meeting held in Montreal, Canada. Generally these meetings are dominated by pharmacological approaches to bone health, but, looking at the big book schedule of lectures, I was delighted to find an entire session on vitamin K.
In this session, several of the top vitamin K researchers reported with disappointment their findings that vitamin K did not seem to improve bone density. I was not too upset by this finding, and really did not expect vitamin K to increase bone density much. Previously, French researchers and others had already noted that higher vitamin K status was inversely correlated with fracture incidence independent of bone density. What I did not expect, however, were the astonishing findings regarding dramatic reductions in both fracture and cancer in postmenopausal women given daily 5 mg of vitamin K1 over 2 to 4 years. The placebo-controlled study, known as the ECKO trial, was conducted by researchers from the University of Toronto, and involved 440 postmenopausal women with osteopenia.
The primary goal, or endpoint, of the study was to see if high dose vitamin K1 (5 mg/day) would increase bone density. The secondary endpoint included changes in bone turnover markers, height, fractures, adverse effects, and health related quality of life. While the study showed no significant changes in bone density over the 2-4 year period, fewer women in the vitamin K group had clinical fractures (9 as compared to 20, a 55% reduction in fractures) and fewer had cancers (3 as compared to 12, a 75% reduction in cancers). Although the study was not designed to test the ability of high dose vitamin K to reduce fractures and cancer, the findings certainly suggest this is a strong possibility.
Years ago at the Center for Better Bones, we identified vitamin D and vitamin K as the two most promising, yet most understudied, bone-building nutrients. The vitamin D story has exploded, as you probably know, and I am sure this remarkable vitamin K1 study and the growing documentation on vitamin K2 in the form of MK-7 are now fueling a vitamin K revolution.
Cheung, Angela, et al. 2008. Vitamin K supplementation in postmenopausal women with osteopenia (ECKO Trial): A randomized controlled trial, PLoS Medicine, 5(10):1461-1472.