Vitamin K is a fat-soluble vitamin.
Phylloquinone; K1; Menaquinone; K2; Menadione; K3
Vitamin K is known as the clotting vitamin. Without it, blood would not clot. Some studies suggest that it helps maintain strong bones in the older adults.
The best way to get the daily requirement of vitamin K is by eating food sources. Vitamin K is found in the following foods:
Vitamin K is also made by the bacteria in the lower intestinal tract.
Vitamin K deficiency is very rare. It occurs when the body can't properly absorb the vitamin from the intestinal tract. Vitamin K deficiency can also occur after long-term treatment with antibiotics.
People with vitamin K deficiency are often more likely to have bruising and bleeding.
Keep in mind that:
The most commonly used anticoagulants currently are not affected by intake of vitamin K. This precaution pertains to warfarin (Coumadin). Ask your health care provider if you need to monitor your intake of vitamin K containing foods and how much you can eat.
The Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should get each day.
The Food and Nutrition Board at the Institute of Medicine Recommended Intakes for individuals - Adequate Intakes (AIs) for vitamin K:
Adolescents and adults
Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 218.
Salwen MJ. Vitamins and trace elements. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 26.
Review Date: 2/2/2019
Reviewed By: Emily Wax, RD, CNSC, University of Virginia Health System, Charlottesville, VA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.