Vitamins are a number of chemically unrelated families of organic substances that cannot be synthesized by humans but need to be ingested in the diet in small quantities to prevent disorders of metabolism.
Vitamin K plays a crucial role in blood clotting. Vitamin K is found in green vegetables such as spinach and broccoli. The liver and pancreas work together to help the body absorb vitamin K from food. Vitamin K deficiency in a health adult is very rare, but a deficiency can develop with long-term antibiotics or with starvation. Symptoms of vitamin K deficiency include easy bruisability, gum bleeding or blood in the urine.
Vitamin K deficiency is common in the newborn, and if vitamin K is not replaced, the infant is at risk for vitamin K deficient bleeding. Vitamin K is given to infants at birth and infant formula is supplemented. High doses of vitamin A or E can also cause vitamin K deficiency.
Blood thinners, such as warfarin, act to block the action of vitamin K and can be reversed with the administration of vitamin K. Vitamin K toxicity is rare and the upper limit for supplementation is not defined.
In addition to its role in blood clotting, vitamin K has role in cardiac and bone health.