Vitamin K is a fat-soluble vitamin that is required for blood clotting and to prevent hemorrhaging. It also plays a role in bone formation and repair. Deficiencies can occur with inadequate dietary intake, malabsorption syndrome, chronic liver disease and in patients taking antibiotics.
There are several forms of vitamin K, including K1, K2 and K3. K1 is the form found in plants such as spinach, broccoli, cabbage, and cauliflower. Vegetable oils such as olive and soybean also contain small amounts of the vitamin. K2 is a form of the vitamin that is synthesized by bacteria in the gastrointestinal tract. Finally, K3 is a synthetic form of the vitamin which is manmade. The synthetic form of vitamin K is routinely given to newborns due to the lack of the vitamin and low amounts of clotting factors, which increases the risk of bleeding in the first few weeks of life. Patients who are on a long term antibiotic treatment are also at risk of vitamin K deficiency and may benefit from supplements. Individuals that are prone to bruising easily and pregnant women may require more vitamin K than others. High doses of vitamin K may be toxic to the fetus in the last trimester of pregnancy and therefore should be avoided. Excessively large amounts of vitamin K should be avoided by people taking anticoagulant medications. Anticoagulants, such as Warfarin, slow blood clotting by interfering with vitamin K activity. Vitamin K reverses the anticoagulant effects which interfere with the effectiveness and safety of anticoagulant therapy. However, vitamin K can be used to counteract an overdose of an anticoagulant and may also be used to reduce fluctuations in dosage requirements of the drug.
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