Alternate Names : Menadione, Phylloquinone, Menaquinones
Vitamin K is a fat-soluble vitamin. It can be dissolved in
fat. Vitamin K is carried through the body by fat and is stored in fat
tissue. There are three forms of Vitamin K:
phylloquinone, which is found in food
menadione, which is man-made
menaquinone, which is produced by the body
The Recommended Dietary Allowance,
called RDA, for vitamin K for adult males, age 25 years and older, is
80 micrograms (mcg) per day. For women, age 25 years and older, it is
65 mcg per day. For pregnant and lactating women, the RDA is also 65 mcg.
Vitamin K deficiency is rare. It is often the result of impaired
absorption rather than not getting enough in the diet. Newborns are
at risk for vitamin K deficiency. This is because their digestive tracts
contain no vitamin K-producing bacteria. For this reason, doctors often give
injections of vitamin K to newborns. The main
symptom of vitamin K deficiency is blood that's slow to clot. Prolonged
use of antibiotics can also cause a low level of this vitamin because
they destroy some of the bacteria in the gut that help to produce vitamin K.
No symptoms are known to result from consuming too much
vitamin K. Moderation is always the best approach. The most toxic form is
supplements. People taking blood thinning medicines, such as
may need to limit their intake of vitamin K-rich foods. This is because the vitamin's
pro-clotting actions can work against this type of medicine.