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Vitamin K (Phytonadione)
Found in:
Spinach, broccoli, brussels sprouts, lettuce, celery, watercress, chicory, beet greens, chard, kale, turnip, parsley, alfalfa,
asparagus, cabbage, cheddar cheese, liver, seaweed, cauliflower, peas, butter, egg, milk, brewed tea and coffee.
What is known to be good for:
Essential for blood clotting and can help maintain bone density. New-born infants are routinely given vitamin K
injections or supplements. In adults and babies, vitamin K helps to regulate blood clotting, maintain healthy bones
and teeth and aids the biosynthesis of helpful bacteria of the gut. Serious problems with blood clotting may arise if you don't take
enough of vitamin K as our blood takes a long time to clot, which may prolong bleeding after injury.
Vitamin K also helps regulate blood calcium levels.
Other functions of Vitamin K:
- Required for the carboxylation of certain glutamate residues of the factor II precursor.
- It is believed that similar vitamin K dependent carboxylations are involved in activation of the other blood coagulation factors.
- Several vitamin K dependent proteins have been identified. Vitamin K is involved in the synthesis of X-carboxyglutamic acid in these proteins.
(The function and significance of these proteins is not clear.)
Lack of Vitamin K can:
Symptoms include prolonged clotting time, easy bleeding, and bruising. This deficiency is rare in adults and normally
limited to those with liver or food absorption disorders. However, it may occur in premature babies.
Excess of Vitamin K can:
Symptoms of vitamin K toxicity include liver damage, hypoprothrombinemia, petechial hemorrhages, renal tubule degeneration, and,
in the premature infants, hemolytic anemia.
Do you know where you find Vitamin K in your body?
Up to half of the human supply of vitamin K is derived from bacterial synthesis in the intestine.
Several vitamin K dependent proteins have been identified. They are located in the bone, kidney and plasma.
Storage and manipulation of suppliers of Vitamin K:
Vitamin K is stable to heat and exposure to air, but is destroyed by light, strong acids, alkalis and oxidizing agents.
Absorption, Storage and Excretion
Absorption of vitamin K, like the other fat soluble vitamins, is dependent upon the presence of bile and pancreatic secretions.
Dietary vitamin K, synthesized by the intestinal microflora, is absorbed from the lower intestine and colon. Vitamin K is incorporated
into chylomicrons and is ultimately transferred to betalipoproteins. The vitamin is not stored in tissues to any great extent.
Source: HEINZ HANDBOOK Of Nutrition, 9th EDITION, Edited by David L. Yeung, Ph.D. and Idamarie Laquatra, Ph.D., R.D.
Adapted by Editorial Department, February 2007
Last update, August 2008
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