Research demonstrates that children are the most deficient of the essential nutrient vitamin K2, creating serious skeletal and vascular implications for growing bodies. Fortunately, there is a simple, proven solution: studies have shown that supplementation with 45-50 mcg of vitamin K2 as MK-7 daily supports bone mineral density, reduces fractures, and may contribute toward cardiovascular health in children – laying the strong foundation for their transition from adolescence into adulthood.
Vitamin K is actually a group of fat-soluble vitamins. It was first recognized for its essential role in the functioning of several proteins involved in blood clotting or coagulation, which is important to prevent excessive bleeding after an injury. In fact, the “K” in vitamin K is derived from the German word “koagulation.” Now, vitamin K is understood to offer additional benefits, including its role activating vitamin K-dependent proteins that are necessary for bone mineralization (e.g., helping to keep calcium in the bone) , as well as utilizing calcium for healthy bones.
The two naturally occurring forms of vitamin K are K1 and K2. Plants synthesize phylloquinone, which is also known as vitamin K1. Friendly intestinal bacteria synthesize a range of vitamin K2 forms collectively referred to as menaquinones. The menaquinone form of vitamin K2 is designated according to the number of repeating 5-carbon units in the side chain of the molecule. For example, if there are seven repeating 5-carbon units, the designation will be menaquinone-7, or MK-7. Vitamin K2 appears to offer the greater range of benefits to human health.
It should be noted that vitamin K2 is available for supplementation as MK-7 and MK-4. In research, peak serum concentration has been recorded at 2 hours after supplementation for MK-4 and 4 hours for MK-7 after intake. However, MK-4 quickly disappears from the circulation (after approximately 8 hours), whereas MK-7 is capable of accumulating in the bloodstream (remains in the body for approximately 72 hours). Supplementation with MK-7 only needs to be taken once a day and is therefore more convenient.
Vitamin K performs important physiological nutritional functions. These include coagulation, bone mineralization and promoting cardiovascular health (through the inhibition of vascular calcification).
Vitamin K-dependent clotting factors, or proteins, are necessary for the coagulation cascade, which is a series of dependent events that stop bleeding through clot formation. Vitamin K-dependent protein Z appears to enhance the action of thrombin and has an anticoagulatory function. Protein C and protein S are also anticoagulant proteins that provide control and balance in the coagulation cascade. Control mechanisms for the coagulation cascade exist because uncontrolled clotting may be as life threatening as uncontrolled bleeding. Vitamin K-dependent coagulation factors are synthesized in the liver.
Vitamin K has been and is still being given to newborns as a shot immediately after birth because vitamin K is needed for normal blood coagulation and the baby’s vitamin K level is usually very low. In 1894, the American pediatrician Charles Townsend discovered that newborns in very rare occasions showed a tendency to bleeding6, but with a different pattern than the typical known bleeding disorders. Nevertheless, such bleeding was serious as the condition could lead to bleeding in the brain (intracranial hemorrhage). Townsend observed that bleeding spontaneously ceased in a 9-day-old infant who received insufficient breast milk and was given formula instead. Thus, the doctor found the link between diet and this type of bleeding. This is because of the multiple coagulation factors must be activated before they can stop the bleeding, and that they are not activated without the presence of vitamin K.
Osteocalcin and matrix Gla protein (MGP) are vitamin-K dependent proteins that have been isolated in bone. Osteocalcin is a protein synthesized by osteoblasts, and is thought to be related to bone mineralization. MGP has been found in bone, cartilage, and soft tissue, including blood vessels. Research suggests MGP prevents the calcification of soft tissue and cartilage, while facilitating normal bone growth and development. Vitamin K may also decrease bone resorption by decreasing prostaglandin E2 synthesis in osteoclasts (cells responsible for the dissolution and absorption of bone), and by effects on calcium balance, and interleukin production in bone. In addition, protein S, a vitamin K-dependent anticoagulant protein, is synthesized by osteoblasts. Although its role in bone metabolism is not clear, children with inherited protein S deficiency suffer complications related to increased blood clotting, as well as decreased bone density. As bone tissue grows and develops most intensively during childhood and adolescence, children have the greatest requirement for active osteocalcin and K vitamins.
The higher peak bone mass children achieve, the lower the risk of poor bone health and potentially osteoporosis when they become elderly. Hence, achievement of optimal pubertal vitamin K status is important to prevent disorders in later life.