The letter K was the first one in the alphabet which had not, with more or less justification, been used to designate other vitamins, and it also happened to be the first letter in the word 'koagulation' according to the Scandinavian and German spelling.
Henrik Dam
In plants, vitamin K is found principally in all kinds of green leaves; leaves which have grown in the dark and therefore have not formed chlorophyll are poor sources.
The discovery of vitamin K arose from some studies on the cholesterol metabolism of chicks carried out during the years 1928-1930 in the Biochemical Institute of the University of Copenhagen.
The hemorrhages in vitamin K deficiency develop in this way that minute vascular lesions caused by minor mechanical trauma are not closed by rapid clotting, as is the case in normal animals.
