What is Vitamin K?
Vitamin K is a fat-soluble vitamin. There are two different forms of Vitamin K (K1=phylloquinone, which is the dietary form, and K2=menaquinones, which are made by the bacteria in our GI tract). We measure K1 on the Comprehensive Vitamin panel.
Vitamin K controls the of coagulation factors - blood components that facilitate clot formation in our bodies and seal wounds after injuries to prevent excessive blood loss. Vitamin K is also involved with bone health and strength.
Plant foods that contain vitamin K include: kale, collard greens, spinach, Swiss chard, mustard greens, turnip greens, Brussels sprouts, broccoli, asparagus, lettuce, green beans, green peas, sauerkraut, soybeans, edamame, pickles, pumpkin, pine nuts, blueberries, kiwi, prunes, soybean oil. Animal sources of vitamin K include: beef liver, pork chops, chicken, goose liver, and fermented cheeses. Consuming plant forms of vitamin K with a small amount of fat has been shown to increase the absorption of vitamin K.
In adults, vitamin K deficiency is relatively rare because vitamin K is found in many foods and the bacteria of the gut also makes vitamin K. Deficiency is mainly a concern because people can experience prolonged bleeding times, but this is usually only seen in severe cases. Individuals at risk for vitamin K deficiency include those with gastrointestinal disorders that cause problems with absorption, such as cystic fibrosis, Celiac disease, ulcerative colitis, prior bariatric surgery or short bowel syndrome. Symptoms associated with a vitamin K deficiency include bruising very easily and having increased bleeding from mucous membranes: nose, gums, gut, and in women excessive menstrual bleeding.
The RDA for vitamin K varies by gender: adult men need 120 mcg/day and adult women need 90 mcg/day.