Does high vitamin K1 intake protect against bone loss in later life?

The findings of a number of cross-sectional studies suggest benefits of high phylloquinone (vitamin K(1)) intake on bone health in later life. Until recently these observational data were supported by the findings of an intervention study that showed a protective role for vitamin K(1) (together with calcium, magnesium, zinc, and vitamin D(3)) on bone loss over 3 years in early postmenopausal women. Over the last 18 months, two further important intervention studies have been published, which investigated the effect of vitamin K(1) on bone loss in older subjects. These two studies add to the evidence-base but cast some doubt on the benefits of high vitamin K(1) intake on bone health in later life.