The existence of this vitamin was postulated by Henrik Dam (1928) who found that chicks maintained on diets low in lipidstend to bleed easily and their blood clots slowly.
Vitamin k exists in nature in at least two forms, vitamin K1 (phytylmenaquinone), in animal andplant tissues, and vitamin K2 (prenylmenaquinone) in microorganisms.
Human hepatic vitamin k pool is composed mainly of menaquinone rather than phylloquinone.
Absorption of vitamin k depends on bile salt secretion and pancreatic lipase activity. Absorption from solubilised preparation is 8 times that from spinach and butter and 33 times better than from spinach alone.
Sources
Vitamin K is found chiefly in leafy green vegetables such as spinach, swiss chard, and Brassica (e.g. cabbage, kale, cauliflower, broccoli, and brussels sprouts); some fruits such as avocado and kiwifruit are also high in Vitamin K.
Deficiency
Average diets are usually not lacking in vitamin K and primary vitamin K deficiency is rare in healthy adults. As previously mentioned, newborn infants are at an increased risk of deficiency. Other populations with an increased prevalence of vitamin K deficiency include individuals who suffer from liver damage or disease (i.e. Alcoholics), people with cystic fibrosis, inflammatory bowel diseases or those who have recently had abdominal surgeries.
Vitamin k exists in nature in at least two forms, vitamin K1 (phytylmenaquinone), in animal andplant tissues, and vitamin K2 (prenylmenaquinone) in microorganisms.
Human hepatic vitamin k pool is composed mainly of menaquinone rather than phylloquinone.
Absorption of vitamin k depends on bile salt secretion and pancreatic lipase activity. Absorption from solubilised preparation is 8 times that from spinach and butter and 33 times better than from spinach alone.
Sources
Vitamin K is found chiefly in leafy green vegetables such as spinach, swiss chard, and Brassica (e.g. cabbage, kale, cauliflower, broccoli, and brussels sprouts); some fruits such as avocado and kiwifruit are also high in Vitamin K.
Deficiency
Average diets are usually not lacking in vitamin K and primary vitamin K deficiency is rare in healthy adults. As previously mentioned, newborn infants are at an increased risk of deficiency. Other populations with an increased prevalence of vitamin K deficiency include individuals who suffer from liver damage or disease (i.e. Alcoholics), people with cystic fibrosis, inflammatory bowel diseases or those who have recently had abdominal surgeries.
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