Vitamin K Functions

Vitamin K is a fat-soluble vitamin needed by the liver to help it create several proteins required to help the blood clot. It also supports proteins involved in bone metabolism and cell growth.

Several foods are rich in vitamin K. vitamin K is found as phylloquinone (vitamin K1) mostly in plant foods like leafy greens and other vegetables, soybeans, and cereals.

Some vitamin K can be made by bacteria in the intestines, although the amount created is not enough to meet your daily needs.

Because vitamin K, like other fat-soluble vitamins, is stored in the liver, deficiencies are uncommon. They might occur because of inadequate absorption of vitamin K caused by long-term use of antibiotics; blood thinning medications; or conditions such as celiac disease, ulcerative colitis, or cystic fibrosis. Those who have chronic diarrhea or are malnourished because of alcoholism or other causes can also become deficient in vitamin K. Signs of a deficiency include increased bruising and bleeding.

Too much vitamin K, though rare, can cause blood clots and promote the breakdown of red blood cells. It can also lead to jaundice.

It’s important for those who take Coumadin or other thinners to monitor their intake of vitamin K from foods and supplements. The Food and Nutrition Board of the Institute of Medicine recommends getting vitamin K only from food sources, not from vitamin K supplements, to prevent excessive intake. If you regularly take a daily multivitamin that has K in it, be sure your doctor adjusts your Coumadin dose.

Ulcerative colitis is an inflammatory bowel disease that causes inflammation and sores in the lining of the rectum and colon; symptoms often include diarrhea.