Vitamin K Health Article

Precautions

Allergic reactions to vitamin K supplements can occur, although they are rare. Symptoms may include flushed skin, nausea, rash, and itching. Medical attention should be sought if any of these symptoms occur. Infants receiving vitamin K injections occasionally suffer hemolytic anemia or high bilirubin levels, noticeable from the yellow cast of the skin. Emergency medical treatment is needed for these babies. Liver and brain impairment are possible in severe cases.

Certain types of liver problems necessitate very cautious use of some forms of vitamin K. Menadiol sodium diphosphate, a synthetic form also known as vitamin K₄, may cause problems in people with biliary fistula or obstructive jaundice. A particular metabolic disease called G6-PD deficiency also calls for careful use of vitamin K₄. The expertise of a health care professional is called for under these circumstances. Sheldon Saul Hendler, MD, PhD, advises there is no reason to supplement with more than 100mcg daily except in cases of frank vitamin K deficiency.

Side effects

Vitamin K₄ may occasionally irritate the gastrointestinal tract. High doses greater than 500 mcg daily have been reported to cause some allergic-type reactions, such as skin rashes, itching, and flushing.

Interactions

There are numerous medications that can interfere with the proper absorption or function of vitamin K. Long term use of antacids may decrease the efficacy of the vitamin, as can certain anticoagulants. Warfarin is an anti-coagulant that antagonizes vitamin K. Efficacy of the vitamin is also decreased by dactinomycin and sucralfate. Absorption is decreased by cholestyramine and colestipol, which are drugs used to lower cholesterol. Other drugs that may cause a deficiency include long-term use of mineral oil, quinidine, and sulfa drugs. Primaquine increases the risk of side effects from taking supplements.

KEY TERMS

Anticoagulant—Substance which inhibits clotting, used therapeutically for such things as stroke prevention in susceptible people.

Billirubin—When gathered in large amounts, this water insoluble pigment occures in bile and blood.

Hemolytic anemia—Destruction of red blood cells.

Hemorrhage—Excessive bleeding.

Prothrombin—One protein component of the cascade reaction which results in clot formation.

BOOKS

Bratman, Steven, and David Kroll. Natural Health Bible. CA: Prima Publishing, 1999.

Feinstein, Alice. Prevention's Healing with Vitamins. PA: Rodale Press, 1996.

Griffith, H. Winter. Vitamins, Herbs, Minerals & Supplements: The Complete Guide. AZ: Fisher Books, 1998.

Jellin, Jeff, Forrest Batz, and Kathy Hitchens. Pharmacist's letter/Prescriber's Letter Natural Medicines Comprehensive Database. CA: Therapeutic Research Faculty, 1999.

Pressman, Alan H., and Sheila Buff. The Complete Idiot's Guide to Vitamins and Minerals. New York: Alpha Books, 1997.

Judith Turner