Vitamin K is a fat-soluble vitamin stored in the liver and the body's fat reserves. It is one of two naturally occurring vitamins in the body and is produced by bacteria that line the gastrointestinal tract. Vitamin K's most important role is in making many of the proteins responsible for blood clotting. It also helps produce a protein called osteocalcin, which plays a crucial role in maintaining healthy bones, healing fractures and preventing osteoporosis.
Some studies indicate that it helps in maintaining strong bones in the elderly.
It can also be found in milk, eggs, beef liver, bran and citrus fruits. However, deficiency may occur in people who have trouble absorbing fats, are on long-term antibiotic therapy, or take other medications such as warfarin and phenobarbital. Symptoms of vitamin K deficiency include easy bruising and ruptured capillaries. A low intake of vitamin K may also increase the risk of hip fractures in women. Garrison R, Somer E. The Nutrition Desk Reference.