Vitamin K has two forms:
Phylloquinone: This form occurs in plants and is consumed in the diet. It is absorbed better when it is consumed with fat. Phylloquinone is not toxic, even in large amounts.
Menaquinone: This form is produced by bacteria in the intestine, but only small amounts of it are produced. In some countries, this form is used for supplementation.
Vitamin K is necessary for normal blood clotting. It is also needed for healthy bones and other tissues.
The effects of vitamin K toxicity can include anemia due to rupture of red blood cells and jaundice. Jaundice in newborns Jaundice in the Newborn Jaundice is a yellow color to the skin and/or eyes caused by an increase in bilirubin in the bloodstream. Bilirubin is a yellow substance formed when hemoglobin (the part of red blood cells... read more can cause kernicterus (a type of brain damage).
(See also Overview of Vitamins Overview of Vitamins Vitamins are a vital part of a healthy diet. The recommended dietary allowance (RDA)—the amount most healthy people need each day to remain healthy—has been determined for most vitamins. A safe... read more .)