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Vitamin K
Vitamin K refers to a group of structurally similar, fat-soluble vitamins that the human body
needs for the synthesis of certain proteins that are required for blood coagulation.
Vitamin K is naturally produced by the bacteria in the intestines.
It is essential for the production of a type of protein called prothrombin & other factor
that are involved in blood clotting
mechanism. Hence it is known as anti -
hemorrhagic vitamins
Vitamin k presents in different forms
1, vitamin k1 ( phyllo quinones)
2,vitamin k2(menaquinones )
3 vitamin k3(menadione)
Vitanmink1 is present in plants ,vitamin k2 produced by intestinal bacteria and vitamin k3
Dietary sources
Cabbage, cauliflower . tomatoes, Spinach ,and other green vegetables ,egg yolk, meat, liver,
cheese and diary product
Recommended daily requirement
There is no recommended daily requirement for vitamin k ,because it is synthesised by some
bacterias present in the gut
So half of the daily requirement is met by the bacterial synthesis and the other half by dietary
intake
Rda of vitamin k is 70-100micro gram/day
Absorption ,transport and storage
It is absorbed along with fat(LDL)with the help of bile salt and is stored mainly in liver
Biochemical functions
Vitamin K is a cofactor for the synthesis of blood coagulation Factors II, VII, IX and X, and
inhibitors such as Protein C and S
clotting factor, II, VIL, IX, X, are Synthesized as inactive ,in liver
In the body vitamin k is converted to its quinone form
With the help of quinone reductase enzyme vitamin k becomes hydroquinone
Hydroquinone the donates one of its electron to the enzyme called gama glutamyl
carboxylase
This enzyme covert clotting factor II, VIL, IX, X to its active form .
