from IV.A - Vitamins
Published online by Cambridge University Press: 28 March 2008
The term “vitamin K” was first introduced by Henrik Dam in 1935, following discovery of a fat-soluble substance that could prevent bleeding (Dam 1935, 1964). During the years 1928 to 1930, Dam conducted studies on the cholesterol metabolism of chicks at the University of Copenhagen. The chicks were being fed an artificial, practically sterol-free diet to which the then known vitamins A and D were added. He observed hemorrhages (bleeding) in different parts of the body in some of the chicks that had been on the diet for more than two or three weeks. In addition, blood that was examined from some of these chicks showed delayed coagulation or clotting (Dam 1964). The low amounts of cholesterol and fat in the diet were ruled out as the causes of the symptom.
Similar observations were made by W. D. McFarlane, W. R. Graham, Jr., and G. E. Hall (1931).W. F. Holst and E. R. Halbrook (1933) observed that the symptoms resembled scurvy, a disease caused by vitamin C deficiency, and could be prevented by addition of fresh cabbage to the diet. These investigators concluded concluded that the protective agent in the cabbage was vitamin C. However, when pure vitamin C became available, it was injected into the chicks and failed to prevent the hemorrhagia (Dam 1964).
Large doses of vitamins A and D (fed in the form of fish-liver oils) and commercial carotene also did not prevent the hemorrhagia (Dam 1935). Cereals and seeds did prevent the symptom, and green leaves and hog liver were found to be potent sources of the antihemorrhagic factor. Research groups led by Dam and H. J. Almquist worked independently to show that the factor was a new fat-soluble vitamin. Dam’s report (Dam 1935) was followed in the same year by that of Almquist and E. L. R. Stokstad (1935). The factor was designated vitamin K (Dam 1935, 1964). According to Dam (1964: 10),“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.”
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