Vitamin K supplementation reduces bone loss

Oral vitamin K (phytonadione and menaquinone-4) is associated with increased bone mineral density and reduced fracture incidence of up to 80% for hip fractures, according to a meta-analysis. Pooling the results of seven trials with fracture outcomes, researchers calculated an odds ratio favoring menaquinone of 0.40 (95% CI; 0.25–0.65) for vertebral fractures, 0.23 (95% CI; 0.12–0.47) for hip fractures, and 0.19 (95% CI; 0.11–0.35) for all nonvertebral fractures.

But the authors of the review caution that the included studies were not designed to show a fracture effect, and such a dramatic effect-much larger than with treatments such as bisphosphonates-could be due to chance, the fact that all the studies with fracture outcomes were performed in Japan, and may be explained by some dietary or other lifestyle factor, or to some other unidentified factor.