MedVitamins VITAMIN K (Menadiol/Phytonadione)

Vitamin K plays a vital role in blood clotting. The vitamin contributes to the liver's synthesis of prothrombin, which converts to thrombin in the initial steps of blood coagulation. Vitamin K is somewhat unique because it has both fat- or water-soluble forms. One form, K-1 or phylloquinone, is found in many plants and animals, and K-2, or menaquinone, is manufactured by microorganisms, such as bacteria, in the intestinal tract of many animals. K-3 (menadione) is a synthetic version with the basic structure of the naturally occurring vitamins and is twice as active biologically. This version is soluble in boiling water.

In either fat- or water-soluble forms, Vitamin K is effective in raising prothrombin levels and controlling hemorrhage in newborns. Newborns do not have the bacteria form of the vitamin and are often given injections of Vitamin K to prevent hemorrhaging. An alternative to injections is oral supplements taken by the mother during the last few days of pregnancy and administered to the child orally after birth.

Vitamin K deficiencies are uncommon but when they do occur, it is usually the result of anti-coagulant medication or the long term use of antibiotics. These medications interfere with the function of the vitamin. Other Vitamin K inhibitors include aspirin, Dilantin, and high doses of Vitamin E. Because Vitamin K is necessary for healthy bones, deficiency poses an increased risk for severe bone fractures.

Vitamin K-1 is the preferred form, as it converts inactive bone protein into a usable form. It is found in green plants and is often used in conjunction with fat-soluble chlorophyll supplements as a treatment for osteoporosis, menorrhagia (excessive menstrual bleeding), and hemorrhagic disease in infants.

Vitamin K is now believed necessary for the formation and maintenance of healthy bones. Researchers in 1994 speculated that two of the Vitamin K-dependent proteins, which were discovered in bone tissue, regulate calcium metabolism, the mineralization of tissue, and bone turnover.1 Animal studies have shown that anti-coagulation therapy might inhibit the formation of bone proteins similar to the effect the therapy has on blood coagulation proteins.

Until recently, it was assumed that intestinal bacterial synthesis of the vitamin met the daily needs of most individuals. But because a large segment of the American population has a low intake of dark green leafy vegetables, researchers at US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University report there now is the possibility of marginal deficiencies.

1. Dowd P, Hershline R, Ham S, et al., Mechanism of action of vitamin K. Nat Prod R 1994;11:251-264.


	VITAMIN K (Menadiol/Phytonadione)
	Vitamin K plays a vital role in blood clotting. The vitamin contributes to the liver's synthesis of prothrombin, which converts to thrombin in the initial steps of blood coagulation. Vitamin K is somewhat unique because it has both fat- or water-soluble forms. One form, K-1 or phylloquinone, is found in many plants and animals, and K-2, or menaquinone, is manufactured by microorganisms, such as bacteria, in the intestinal tract of many animals. K-3 (menadione) is a synthetic version with the basic structure of the naturally occurring vitamins and is twice as active biologically. This version is soluble in boiling water. In either fat- or water-soluble forms, Vitamin K is effective in raising prothrombin levels and controlling hemorrhage in newborns. Newborns do not have the bacteria form of the vitamin and are often given injections of Vitamin K to prevent hemorrhaging. An alternative to injections is oral supplements taken by the mother during the last few days of pregnancy and administered to the child orally after birth. Vitamin K deficiencies are uncommon but when they do occur, it is usually the result of anti-coagulant medication or the long term use of antibiotics. These medications interfere with the function of the vitamin. Other Vitamin K inhibitors include aspirin, Dilantin, and high doses of Vitamin E. Because Vitamin K is necessary for healthy bones, deficiency poses an increased risk for severe bone fractures. Vitamin K-1 is the preferred form, as it converts inactive bone protein into a usable form. It is found in green plants and is often used in conjunction with fat-soluble chlorophyll supplements as a treatment for osteoporosis, menorrhagia (excessive menstrual bleeding), and hemorrhagic disease in infants. Vitamin K is now believed necessary for the formation and maintenance of healthy bones. Researchers in 1994 speculated that two of the Vitamin K-dependent proteins, which were discovered in bone tissue, regulate calcium metabolism, the mineralization of tissue, and bone turnover.1 Animal studies have shown that anti-coagulation therapy might inhibit the formation of bone proteins similar to the effect the therapy has on blood coagulation proteins. Until recently, it was assumed that intestinal bacterial synthesis of the vitamin met the daily needs of most individuals. But because a large segment of the American population has a low intake of dark green leafy vegetables, researchers at US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University report there now is the possibility of marginal deficiencies. 1. Dowd P, Hershline R, Ham S, et al., Mechanism of action of vitamin K. Nat Prod R 1994;11:251-264.