Functions

Vitamin K, or phylloquinone (K1= hytonadione; K2=menaquinone; K3=menadione), is essential for the synthesis of five proteins involved in blood clotting. It is also involved with calcium in the development of bone. It is also involved in the production of a urinary protein involved in kidney function which inhibits the formation of calcium oxalate kidney stones.

Uses

Used for blood coagulation; osteoporosis; floaters; n&v of pregnancy; fractures; RA, inflammation; Ca oxalate stones; pruritis; cofactor in protein synthesis; for the elderly.

Deficiency

Vitamin K deficiencies may occur with the extended use of antibiotics, fat malabsorption; the sterile digestive tract of newborns may contribute to hemorrhagic disease of the newborn, easy bleeding, osteoporosis.

Antagonists

Freezing may destroy Vitamin K but it remains stable when heated.

Co-factors

Vitamin K is absorbed in the small intestine, with the use of bile salts from the liver/gallbladder. It is stored in th liver in small amounts - about a 10 day supply. Vitamin K can be derived from bacterial die-off in the gut.

Drug Interactions

X rays and radiation, aspirin, cholestyramine, the anticonvulsant phenytoin and mineral oil laxatives can raise vitamin K requirements. Some snake venoms act by destroying vitamin K, thus causing uncontrolled bleeding.

Vitamin K may be injected to stop the bleeding. Long-term use of antibiotics may produce vitamin K deficiency as these drugs can kill not only harmful bacteria but also the beneficial bacteria which produce vitamin K.

Dose

The RDA for vitamin K is 1 mcg per kg of body weight. It is assumed that half the necessary daily intake comes from intestinal bacteria. Therapeutic dose is 1-10 mg.

Toxicity

Thought to be rare, Vitamin K toxicity causes red cell hemolysis, jaundice, and brain damage. There is thought that persons on anti-coagulation therapy should avoid vitamin K. Few signs of toxicity with naturally consumed vit K (K1 & K2); with synthetic there may be flushing; sweating; chest constriction; in infants:hemolytic anemia, kernicterus.

Sources

Vitamin K sources include green leafy vegetables, vegetable oils, soybean oil, wheat bran, liver, milk, meats, and egg yolk. K1 in chlorophyll, turnip greens, broccoli, cabbage, beef liver; K2 made by intestinal bacteria (is fat soluble) K3 is synthetic, water soluble