Vitamin
K occurs primarily in plants; it is also synthesized by intestinal bacteria
in the small intestine. Vitamin K is necessary for the synthesis by the liver of
the blood clotting enzyme prothrombin. It is fat-soluble and is sensitive to
light, oxygen, strong acids, and alcoholic alkalis.
The following quantitative list presents both plants and plant products containing significant amounts of this nutrient, in approximate order from highest to lowest content for a given weight. Unless otherwise noted, all items are fresh and unprocessed. Dried fruits are often included without their fresh equivalents because the dried versions weigh considerably less and therefore contain more nutrients than the same weight of fresh fruit:
