Vitamin K Status in Children Improves Bone Health in New Study

05/03/08 A better vitamin K status was associated with more pronounced increase in bone mass in healthy children – yet western populations are likely vitamin K deficient

NattoPharma, Norway, and P.L. Thomas have noted the publication of a new study demonstrating vitamin K's role in promoting healthy bones in children. Published online at the British Journal of Nutrition link, the researchers followed 307 healthy children, with an average age of 11.2 years, over a two year period and measured skeletal bone mineral content. They found improved status of the K vitamins over the two year period resulted in better mineral content and improved bone mass of the whole body.

According to the lead author, Marieke Summeren, Ph.D., "As children grow the increase in bone mass may fail to keep up with the increase in height, or length of the bone, and as a consequence, this imbalance may result in fracture." She continued, "But the main threat of a long-term shortage of K vitamins is that peak bone mass may be compromised, and as we age and begin to lose bone density, the risk of fracture in later life is increased."

Study author Leon J. Schurgers,Ph.D.commented, "Numerous population studies and interventional trials have established the consumption of K vitamins to bone strength, structure and the reduction of the risk of fracture. This is due to the need to activate the vitamin K-dependent protein osteocalcin, which is essential for the body to utilize calcium in a healthy bone tissue. Unfortunately, most people, including children, are likely deficient in the K vitamins related to the need for bone health."

This is among the first studies linking K vitamins to bone health in children. Vitamin K status was evaluated by measured by the amount of active osteocalcin to inactive osteocalcin. Without adequate vitamin K, the osteocalcin remains inactive, and thus not effective. Previous research has evaluated vitamin K status in children and found that they have inadequate K vitamins consumption to fully activate osteocalcin.

"There are two types of vitamin K from dietary sources. Vitamin K1 is found in leafy green vegetables, and Vitamin K2, also called menaquinones, are predominately found in fermented cheeses, curd, and the fermented soy called natto," stated Schurgers. "Vitamin K1 is mostly used by the liver where it is involved in the synthesis of certain blood clotting factors. Vitamin K2 is also equally active outside the liver, in tissues including bone. Thus it is important to have good sources of both types of vitamin K!"

The recommended intakes of vitamin K today are based solely on coagulation. However, K vitamins are also necessary for the activation of osteocalcin, a protein necessary to transport calcium from the blood to form healthy bone matrix. Also, K vitamins are needed to activate matrix GLA protein (MGP), the most potent inhibitor of vascular calcification known. In essence, K vitamins are necessary to keep calcium in your bones and out of your arteries.

The role of newly recognized vitamin K2 has for the past decade been linked to two of the most important health issues, osteoporosis and cardiovascular disease. This link specifically centers on calcium utilization- implying that there is concurrent arterial calcification and osteoporosis when metabolism of calcium is inadequate. K vitamins are essential to activate proteins involved in calcium metabolism.

Numerous population studies and interventional trials have established the consumption of vitamins K and K2 to bone strength, structure and the reduction of the risk of fracture. More recently, and specifically to vitamin K2, a significant role in cardiovascular health has been established.

A study published in the Journal of Nutrition called the "Rotterdam Study" in 2004, followed over 4,800 people for a ten year period. The study found increased intake of specifically vitamin K2 from dietary sources significantly reduced the incidence of arterial calcification and the risk of CHD mortality by 50% as compared to low dietary vitamin K2 intake. In this study, vitamin K1 had no effect at all.