The Institute of Medicine recommends that women get 90 micrograms of vitamin K per day, while men should get 120 daily micrograms. Vitamin K takes its name from the German word “koagulation” for a good reason — its most important function in your body is to assist clotting factors that prevent excessive bleeding when you are injured. Vitamin K also helps your body build new bone material, possibly protecting against osteoporosis as you age.
Chlorophyll
Plants get their green pigment from chlorophyll, a molecule that also contains vitamin K. Therefore, leafy green vegetables, which contain large concentrations of chlorophyll, are rich in this vitamin. A 2-cup serving of spinach gives you 290 micrograms of vitamin K, more than 100 percent of your recommended daily intake. Cooking doesn’t deplete food of this nutrient. A cup of cooked spinach provides 888 micrograms of vitamin K. Beef liver, broccoli, green tea, kale, asparagus and cabbage are also sources of vitamin K.
Blood Clotting
When you are wounded, the proteins in your blood need an adequate amount of vitamin K to help activate seven clotting factors that bind calcium ions in your blood, coagulating it and making the bleeding stop. If you bruise easily or frequently experience nosebleeds, bleeding gums or a heavy menstrual flow, you may have thin blood, putting you at risk for excessive bleeding in the case of an injury. Adding vitamin K to your diet may help you control these conditions.
Bone Building
You may take calcium and vitamin D to keep your bones strong, but vitamin K also plays a role in bone health. Two proteins, osteocalcin and matrix Gla protein, need the presence of vitamin K to generate new bone and cartilage material, according to authors of an article published in “Advances in Nutrition” in 2012. People with larger concentrations of vitamin K in their bodies tend to have greater bone density than those with low levels of vitamin K, according to the University of Maryland Medical Center, and people with osteoporosis often show low levels of vitamin K.
Warning
Whether you choose to increase your intake of vitamin K-rich foods or add a vitamin K supplement to your current balanced diet, remember that it is fat-soluble, so your body stores any excess in your liver and organs. Although the IOM has not established a safe upper limit, mega-dosing of this nutrient could lead to a breakdown of red blood cells and liver damage, according to Colorado State University Extension. To stay safe, take only the recommended amount of vitamin K.
References
- University of Maryland Medical Center: Vitamin K
- Linus Pauling Institute: Vitamin K
- Institute of Medicine: Dietary Reference Intakes
- United States Department of Agriculture Nutrient Database: Spinach, Cooked
- United States Department of Agriculture Nutrient Database: Spinach, Raw
- Advances in Nutrition: The Role of Vitamin K in Soft-Tissue Calcification
- Institute of Medicine: Tolerable Upper Intake Levels
- Colorado State University Extension: Fat-Soluble Vitamins — A, D, E and K