Vitamin K Shown to Improve Bone Mineral Density
Vitamin K is an essential nutrient necessary for blood clotting that has also been associated with bone health. A new study has shown that different forms of vitamin K may increase bone mineral density and reduce the risk of osteoporosis in postmenopausal women.
Published in the April 2012 issue of Calcified Tissue International, the study examined the effects on bone density of combining calcium and vitamin D with the two primary forms of vitamin K—phylloquinone (vitamin K1) and menaquinones (vitamin K2).
The researchers recruited postmenopausal women and placed them in three groups: two interventions and a control. While all three groups received 800 mg of calcium and 10 mcg vitamin D3 daily, one intervention group also consumed 100 mcg of vitamin K1 and the other intervention group consumed the same amount of vitamin K2.
After 12 months, the researchers observed higher total-body bone mineral density (BMD) in all three groups but observed increased BMD in the lumbar spine only in the intervention groups. When lumbar spine BMD is increased, the risk of vertebral fractures decreases.
The researchers believe the vitamin K-enriched supplement increased serum levels of osteocalcin. Osteocalcin is a protein that allows the body to utilize calcium in bone tissue and relies on vitamin K in order to become active.
Vitamin K1 can be found in leafy green vegetables and some oils but it has a very short half-life, meaning it loses half of its potency in 1-2 hours. As a result, increasing your K1 intake through diet alone can be very difficult. Vitamin K2 on the other hand has a much longer half life and is better absorbed. Foods high in vitamin K2 include cheese, egg yolk, chicken liver and ground beef.