Some Important Aspects about Vitamin K

ID-100209371There are two natural forms of vitamin K and they are vitamin K1 and vitamin K2. Vitamin K1 is also known as phylloquinone and vitamin K2is also known as menaquinone. Phylloquinone can be converted to menaquinone in some organs in humans.

Sources of vitamin K1:

Vitamin K1 is found mainly in the dark green leafy vegetables like kale and spinach. Vitamin K is present in vegetable oils also and it is particularly rich in olive, canola, and soybean oils. Margarine and liver also contain good quantity of vitamin K1. Cow’s milk (60 micro gram /liter) is a richer source of Vitamin K than human milk (15 micro gram /liter).

Vitamin K2 is synthesized in the intestines by intestinal flora (bacteria), which can usually supply adequate quantity of vitamin Kin humans. Vitamin Kis stored in liver and adipose tissues (fat store) in humans. If antibiotics are taken for long term (usually more than a week), it can suppress the normal intestinal flora that are sources of vitamin K2 and can cause deficiency of vitamin K.

Vitamin K is required to stimulate the production and release of certain blood coagulation factors. Vitamin K is required for the posttranslational carboxylation of glutamic acid, which is must for calcium binding to ?-carboxylated proteins such as prothrombin (blood coagulation factor II), factors VII, IX, and X. in vitamin K deficiency the prothrombin content of blood is reduced and the blood coagulation time is prolonged considerably.

Recommended daily allowance (RDA) of vitamin K: The recommended daily allowance of vitamin K in humans is approximately 100 mcg (micro gram) per day. This RDA is generally met in humans by combination of dietary sources and microbial synthesis in intestine by intestinal flora.

Infants usually have lower level of vitamin K, due to non establishment of intestinal flora, low breast milk (15 micro gram/liter) levels of vitamin K, liver immaturity, and poor placental transport and also due to low fat content where vitamin K is stored.


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