Vitamin K is a fat soluble vitamin that is stored in fatty tissue in the body. It is mostly found in vegetables, but is also contained in cereals. Cabbage, broccoli, asparagus, spinach and other leafy green vegetables are high in vitamin K. Vitamin K is derived from chlorophyll, the same substance that gives plants their green color. Vitamin K can also be found in multivitamins or as a separate supplement.
Blood Clotting
The main function of vitamin K is coagulation, the formation of blood clots. Blood clots are needed to stop the loss of blood from the body as a result of broken blood vessels. Vitamin K deficiency is rare, but can cause increased bruising or excessive bleeding, especially from the gums or nose. Since newborns lack sufficient vitamin K, they are injected with vitamin K to prevent excessive bleeding from occurring, especially in the brain. Premature newborns are at an increased risk for vitamin K deficiency.
Bone Fractures
Vitamin K aids in the development of healthy bones. As a result, vitamin K reduces the propensity for bone fractures. The risk of hip fractures as a result of vitamin K deficiency was the focus of a study published in the January 1999 issue of "The American Journal of Clinical Nutrition." This study found that people who consumed one or more servings of lettuce per day were at reduced risk of hip fracture.
Bone Density
Loss of bone density, or osteoporosis, is the most common type of bone disease. It is associated with a lack of calcium, which is one of two minerals involved in the formation of bones. Vitamin K helps to facilitate the use of calcium in bone formation. As a result, there is a significant relationship between bone density and vitamin K. Specifically, higher levels of vitamin K are associated with greater bone density. In a study published in the 2003 issue of "The American Journal of Clinical Nutrition," researchers found an association between low vitamin K consumption and bone mineral density in women over age 50, whereas no association was found among men over age 50.
Warnings
Since Vitamin K is responsible for the formation of blood clots, it can interfere with blood thinners such as warfarin, or Coumadin. Blood thinners may be prescribed to prevent heart attacks or strokes, which are caused by significant clotting. Taking vitamin K or eating foods high in vitamin K can cancel the effects of blood thinners. The absorption of vitamin K may be hindered by antibiotics, leading to a vitamin K deficiency when taken for more than 10 days.
References
- Medline Plus: Vitamin K
- University of Maryland Medical Center: Vitamin K
- "The American Journal of Clinical Nutrition"; Vitamin K Intake and Hip Fractures in Women: A Prospective Study; D. Feskanich, et al.; January 1999
- PubMed.gov: Osteoporosis
- ""The American Journal of Clinical Nutrition"; Vitamin K Intake and Bone Mineral Density in Men and Women; S.L. Booth et al.; February 2003
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