In healthy subjects, there is no known safety risk associated with high doses of vitamin K1 (phylloquinone) or vitamin K2 (menaquinone) forms of vitamin K (27).

Tolerable upper intake levels

No tolerable upper level (UL) of intake has been established for vitamin K (27, 39).

Nutrient interactions

Large doses of vitamin A and vitamin E have been found to counteract vitamin K (5). Excess vitamin A appears to interfere with vitamin K uptake, whereas a form of vitamin E (tocopherol quinone) may inhibit vitamin K-dependent enzymes (40).

Drug interactions

Please note:

Because of the potential for interactions, dietary supplements should not be taken with medication (e.g., oral anticoagulants) without first talking to a knowledgeable healthcare provider.

Authored by Dr Peter Engel in 2010, reviewed and updated by Dr Szabolcs Peter on 18.06.2017

This site uses cookies to store information on your computer.

Learn more