Researchers from the University of Maastricht, Netherlands, followed 325 postmenopausal women without osteoporosis with an average age of 66 and an average body mass index of 27 who were overweight but not obese. Scientists gave the women a placebo or 15 mg of vitamin K2 (MK-4, menatetrenone) three times per day for three years.
The doctors noted that the MK-4 form of vitamin K2 is synthetic and only remains in the body for several hours compared to menaquinone (MK-7) the natural form of vitamin K2, which remains in the body for several days. The doctors explained this is why the dosage in the study was higher than the typical dose for vitamin K2.
At the start of the study and after each year, researchers measured the amount of minerals in the bone and bone strength. After three years, those who had taken vitamin K2 had increased bone mineral content and width of the hip bone (femoral neck) compared to placebo. Doctors noted the femoral neck is the part of the hip that fractures most frequently in the elderly. Overall, researchers reported that bone strength remained unchanged in those who had taken vitamin K2, while it decreased significantly in the placebo group.
Doctors concluded that vitamin K2 increased the bone mineral content and width at the femoral neck, allowing this important part of the hip to remain strong, even though overall bone mineral density (BMD) declined after menopause, and suggested that manufacturers create a low-dose supplement using the natural menaquinone MK-7 form of vitamin K2.