The study, published in the Journal of Bone and Mineral Metabolism, included 115 postmenopausal women who were divided into three treatment groups and one control group.
All of the treatment groups attended nutrition and lifestyle counseling sessions every two weeks and ate fortified milk and yogurt portions for one year. The dairy portions were made to provide either 800 mg of calcium and 10 mcg (400 IU) of vitamin D or the same amounts of calcium and D plus 100 mcg of vitamin K1 or 100 mcg of vitamin K2 every day.
Vitamin K1, or phylloquinone, is the form of vitamin K made by plants. The menaquinones, a group of compounds that are collectively called vitamin K2, are produced by bacteria and are also found in some foods, such as cheese and fermented soy.
The type of vitamin K2 that was used in this study (menaquinone-7 or MK-7), may have more biological activity than vitamin K1.
When researchers compared bone mineral density measurements from the beginning and end of the study, they observed:
The preservation of bone seen in the treatment groups might reflect a reduced fracture risk, although we can’t know for sure from this study, because, even though higher bone mineral density is usually associated with lower risk of fracture in general, it isn’t always.
“Our findings showed that the holistic approach followed in the current study, combining nutrition and lifestyle counseling with the consumption of fortified milk and yogurt, managed to induce favorable changes in dietary intake indices (calcium, vitamin D and vitamin K) and physical activity levels, as well as in total body bone mineral density,” the study’s authors concluded. “Furthermore, an additional benefit was observed for lumbar spine bone mineral density for the groups supplemented with vitamin K1 and K2, probably indicating a site-specific skeletal effect of this nutrient.”
Supplementing with bone-specific nutrients appears to be a good idea, but don’t forget to incorporate healthy diet and physical activity into your equation for bone health:
(J Bone Miner Metab 2011;29:501–6)