vitamin K - essential to human health

Can Vitamin K Help Prevent and Treat Osteoporosis?

Vitamin K and vitamin K2 may help strengthen bones in some people at risk of osteoporosis, especially if combined with vitamin D and calcium.

Osteoporosis is a condition where bone tissue becomes less dense over time. Loss of bone density significantly increases the risk of bone fractures. Some studies suggest that vitamin K may help treat or prevent osteoporosis, but results are controversial.(53)

Who Is at Risk of Osteoporosis?

Although it can affect both older men and women, it is recognized as a major health issue for postmenopausal women since decreases in the hormone estrogen can result in increases in demineralization of bone.(53)

How Can Vitamin K Help?

Vitamin K is important for healthy bones because of its interactions with bone proteins. Through a process called carboxylation, vitamin K changes these proteins so they can bind to calcium, an important mineral for bones:(142253)

Table 5: Proteins in Bone Vitamin K Carboxylates
Protein Importance in Bone Health

Plays a role in:

  • Bone mineralization.
  • Bone density.
  • Facilitates normal bone growth.
  • Prevents calcification of soft tissues.
Protein S The role of protein S in bone density is unclear, except that children born with a deficiency in this protein have reduced bone density.

Vitamin K deficiency can result in non-carboxylated proteins. Higher blood serum levels of non-carboxylated bone proteins are linked to reduced bone density and greater risk of bone fracture in elderly women. Additionally, research indicates that drugs that block vitamin K activity (e.g., anticoagulant drugs) may reduce bone density in the arm.(142253)

Preclinical and Clinical Evidence

Studies have shown that postmenopausal women and elderly men who take vitamin K1 supplements have increased levels of carboxylated bone proteins. Whether or not use of vitamin K supplements improves bone density and decreases risk of fractures is still unclear, however, because of conflicting study results.(1)

Vitamin K Supports Bone Health if There's Vitamin K Deficiency

Research shows a link between vitamin K levels and bone health in older populations or in patients with diseases that cause vitamin K deficiency and increased risk for osteoporosis. Animal and clinical studies suggest vitamin K2 or vitamin K1 in combination with other supplements may help:

  • Crohn's Disease. Vitamin K deficiency in patients with Crohn's disease has been linked to increased bone resorption and decreased bone density of the lumbar spine.(1)
  • Steroid-Associated Bone Loss. Results of animal studies suggest that vitamin K2 may prevent bone loss due to prednisolone (a steroid).(54)
  • Organ Transplant Patients. Vitamin K2 may help prevent osteoporosis in organ transplant patients, a group vulnerable to this condition. In a randomized, placebo-controlled clinical trial, 94 heart or lung transplant patients were treated with 180 µg/day of vitamin K2 for one year. Measurements showed that vitamin K2 helped maintain bone density in the spine. Since reduced bone density is related to osteoporosis, this suggests vitamin K2 may help reduce the risk of developing osteoporosis in transplant patients.(55)
  • Post-Menopausal Women. In a 14-week controlled study involving 33 healthy postmenopausal women, combining several supplements (including 500 µg of vitamin K) with low-glycemic dietary intake (similar to a Mediterranean diet) and mild exercise significantly reduced markers for bone turnover. The untreated placebo group, on the other hand, exhibited a 19% increase in these markers, which are indicative of less healthy bone metabolism.(53)

    Vitamin K combined with vitamin D and calcium supplements may also be beneficial. Results of a clinical study involving post-menopausal Korean women showed that taking the supplements for 6 months increased bone density. Levels of under-carboxylated bone proteins were also reduced.(56)

    Vitamin K2 has been found to promote bone formation in postmenopausal women.(54)

  • Cirrhosis of the Liver. Patients with liver disease often experience bone loss. Results of a randomized, controlled clinical study of 50 women with cirrhosis of the liver and underlying hepatitis viral infections suggest that vitamin K2 may help prevent bone loss in these patients. Over the course of the 2-year study, study participants in the vitamin K2-treated group had significantly smaller decreases in bone density than the control group. There were no adverse side effects from the vitamin K2 reported.(57)

Vitamin K2 and Reduced Bone Fractures

Clinical studies suggest vitamin K2 may also prevent new fractures in patients with osteoporosis.(54)

Reports of No Benefit on Bone Density from Vitamin K in Some Populations

Conversely, some research showed that increased vitamin K intake, by itself, showed no benefit for bone density in some groups:

  • In elderly populations of men and women, oral vitamin K supplements increased levels of bone proteins. However, they did not appear to increase bone density, which is associated with lower risk of bone fracture.(1)
  • Researchers analyzed dietary intake of vitamin K for premenopausal women. They found no link between bone density and the level of dietary vitamin K in a population study of Danish women.(3)

Bottom Line

It is difficult to figure out if assess the benefit of vitamin K on osteoporosis based on bone density alone. This is due to the wide array of study types involving disparate populations and different forms of vitamin K.(3)

However, a 2006 meta-analysis was conducted on similar type studies measuring bone density and fracture risk. The researchers concluded that vitamin K supplementation (primarily vitamin K2) does offer bone-strengthening benefits - particularly for Asian people. Vitamin K may also be helpful in some people at risk for vitamin K deficiency, particularly when combined with other supplements or healthy diets.(353-57)

However, these same vitamin K antagonists apparently have no effect on the hip and back bones.(1)
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