Supplements: Vitamin K

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Vitamin K

Vitamin K is best known for its role in helping blood clot properly, and in preventing excessive bleeding. It also plays an important role in bone health.


Vitamin K protects the body against the following.

  • Bleeding. Vitamin K is used to reduce risk of bleeding in liver disease, jaundice, malabsorption, or in association with long-term use of aspirin or antibiotics.
  • Vitamin K has been used in the treatment of heavy menstrual bleeding, and with vitamin C to treat morning sickness.
  • Babies are sometimes given a vitamin K injection soon after birth, because in certain cases, such as in premature infants, they are at increased risk for bleeding.
  • Osteoporosis. Vitamin K is needed for bones to use calcium.
  • Vitamin K supplements may improve bone mass in postmenopausal women.
  • Vitamin K deficiency is linked to osteoporosis because low levels have been found in those with the condition.
  • Supplements of vitamin K have been used to treat osteoporosis.

Vitamin K also helps in the following ways.

Vitamin K may prevent kidney stones. A vitamin K analog, K compound 5, may stop liver cancer growth. Some forms (water-soluble chlorophyll) help control body, fecal, and urinary odor. Water-soluble forms are used to treat skin wounds.

Dietary Sources

Foods that contain a significant amount of vitamin K include chlorophyll, green tea, turnip greens, broccoli, spinach, cabbage, asparagus, and dark green lettuce.

Freezing foods may destroy vitamin K, but heating does not affect it.

Other Forms

Vitamin K supplements are available in both natural and synthetic forms. Supplements of fat-soluble chlorophyll are an excellent source of vitamin K. Water-soluble chlorophyll is the most common form of vitamin K found over the counter. The water-soluble form is not absorbed into the body, and is useful for treatment of skin, and to reduce body odor. Vitamin K is available in multivitamin complexes, and as 5-mg tablets.

How to Take It

The recommended dietary allowance (RDA) for vitamin K is 80 mcg for men, and 65 mcg for women. To help prevent and treat disease, increase the amount of dark green leafy vegetables you eat, and supplement your diet with up to 500 mcg of vitamin K each day.

As with all medications and supplements, check with a health care provider before giving vitamin K supplements to a child.


  • Vitamin K can interfere with the action of anticoagulants such as warfarin or coumadin.
  • X-rays and radiation can raise vitamin K requirements.
  • Vitamin K is excreted in breast milk, and crosses the placenta.
  • Pregnant women and women who are breast-feeding should consult their health care provider before starting vitamin K supplements.
  • Your body may need more vitamin K if you are taking aspirin, cholestyramine, phentoin, or mineral oil laxatives.
  • Some snake venoms destroy vitamin K, which helps blood clot properly. Vitamin K may be injected to stop the bleeding from snakebite.
  • Extended use of antibiotics may result in vitamin K deficiency.
  • These drugs kill not only harmful bacteria, but also beneficial, vitamin K-activating bacteria.

Possible Interactions

  • Natural vitamin K taken orally is generally nontoxic.
  • Large doses of the synthetic form of vitamin K, which you may get to prevent bleeding in certain conditions, may cause anemia and liver damage.
  • Injections of vitamin K can cause flushing, sweats, chest pain, and constricted breathing.
  • Blood problems, jaundice, and liver problems have been seen in newborns after they are given vitamin K. I
  • ntramuscular injections of vitamin K may cause pain, swelling, and eczema.

This document contains information relating to general principles of medical care that should not in any event be construed as specific instructions for individual patients. The reader is advised to check product information (including package inserts) for changes and new information regarding dosage, precautions, and contraindications before administering any drug. No claim or endorsements are made for any drug or compound currently in investigative use. No responsibility is assumed by the publisher for any injury and/or damage to any person or property as a matter of product liability, negligence, or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in any material herein.

This web site is intended for your own informational purposes only. No person or entity associated with this web site purports to be engaging in the practice of medicine through this medium. The information you receive is not intended as a substitute for the advice of a physician or other health care professional. If you have an illness or medical problem, contact your health care provider. You should consult your health care provider with any questions about the nature or effect of products you purchase here. Be sure to read all directions, warnings and other information accompanying any product before using it.

Dietary supplements are not intended to treat, cure, or prevent any disease or illness, and the information regarding these products has not been evaluated by the U.S. Food and Drug Administration.

 Material © Healthquick Inc.    Used by permission

Previously Published in OSA Today Reproduced by permission

Updated on: 03/10/16
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