In a study involving postmenopausal women divided into 4 groups (1 control group plus 3 intervention groups all of whom attended biweekly sessions and received fortified dairy products containing calcium and vitamin D3; in 2 of the groups, the dairy was also enriched with vitamin K1 or K2), significant increases in serum total body bone mass density (BMD) were found in all 3 intervention groups, but significant increases in the BMD of the lumbar spine was found only in the groups also fortified with vitamin K1 or K2, as compared to the control group.