Vitamin K is a fat soluble vitamin that is essential for normal blood clotting. Its role is so large -- it produces six of the 13 proteins needed for blood clotting -- that a Vitamin K deficiency can cause serious bleeding disorders. Vitamin K deficiency is rare in adults, but the supplement is routinely given to newborn infants to prevent bleeding problems related to birth, or if surgery is planned.

Effect on your health

Though most commonly used to treat and prevent bleeding problems, Vitamin K may also help build bone and protect against osteoporosis. Research has linked low levels of Vitamin K to low bone density, while new studies link Vitamin K supplementation to improved bone density and a reduced a chance of fractures. Although Vitamin K deficiency is rare, several conditions can increase the risk, including chronic malnutrition, cystic fibrosis, celiac disease, ulcerative colitis, short bowel syndrome, and regional enteritis. In addition, many drugs can reduce Vitamin K levels by interfering with liver function or by killing the intestinal bacteria that make Vitamin K. Such drugs include antibiotics, salicylates, anti-seizure medications, and some sulfa drugs.

What is the recommended daily dosage of vitamin K?

It is recommended that men get at least 80 micrograms, and women at least 65 micrograms, of Vitamin K daily. Vitamin K is found in several foods, especially green leafy vegetables. Good sources of Vitamin K include spinach, broccoli, asparagus, watercress, cabbage, cauliflower, green peas, beans, olives, canola, soybeans, meat, cereals, and dairy products. Cooking does not deplete much Vitamin K, so a diet rich in these foods should provide adequate amounts of the vitamin. Vitamin K is available in both an oral doses and injections. It should not be taken with anticoagulants such as warfarin, because it can interfere with the medication’s effectiveness. Vitamin K can also interact negatively with several medical conditions, including pancreatic diseases, gallbladder disease, prolonged diarrhea, intestinal problems, liver disease, and glucose-6-phosphate dehydrogenase deficiency. It should be stored away from heat and light, in a dry place, and between 59 and 86 degrees Fahrenheit. Although it is not known to cause birth defects, Vitamin K should be used with caution in children, who may be more sensitive than adults.