Vitamin K deficiency is rare, but can occur in newborn infants. They are at higher risk, because there is poor transfer of vitamin K across the placental barrier, their gastrointestinal tracts do not contain vitamin K producing bacteria, and breast milk is generally low in vitamin K1. As a result, it is recommended (and widely practiced) that all infants receive a vitamin K injection within 6 hours of birth2.
Prolonged antibiotic treatment (which kills bacteria in the gastrointestinal tract) and lipid absorption problems can also lead to vitamin K deficiency3. Vitamin K deficient individuals have an increased risk of bleeding or hemorrhage. Remember that high levels of vitamin E intake can also interfere with vitamin K's blood clotting function. It is believed that a vitamin E metabolite, with similar structure to the vitamin K quinones, antagonizes the action of vitamin K.
Phylloquinone and menaquinone have no reported toxicities. However, menadione can cause liver damage1.
References & Links
1. Gropper SS, Smith JL, Groff JL. (2008) Advanced nutrition and human metabolism. Belmont, CA: Wadsworth Publishing.
2. Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J. (2009) Wardlaw's perspectives in nutrition. New York, NY: McGraw-Hill.
3. McGuire M, Beerman KA. (2011) Nutritional sciences: From fundamentals to food. Belmont, CA: Wadsworth Cengage Learning