Vitamin K refers to a group of structurally similar, fat-soluble vitamins the human body needs for complete synthesis of certain proteins that are required for blood coagulation, and also certain proteins that the body uses to manipulate binding of calcium in bone and other tissues.
Vitamin K is named after the German word for blood clotting (koagulation). In fact, this is probably the most common connection that people make with vitamin K—they associate this vitamin with the process of blood clotting. It’s important to know that vitamin K makes a variety of unique contributions to our health, and our knowledge about these contributions has been expanding in new and unexpected ways.
There are three basic types of vitamin K. Their common names are K1, K2, and K3.
The vitamin K-related modification of the proteins allows them to bind calcium ions, which they cannot do otherwise. Without vitamin K, blood coagulation is seriously impaired, and uncontrolled bleeding occurs. Low levels of vitamin K also weaken bones and promote calcification of arteries and other soft tissues.
- Green leafy vegetables, such as kale, spinach, turnip greens, collards, Swiss chard, mustard greens, parsley, romaine, and green leaf lettuce.
- Vegetables such as Brussels sprouts, broccoli, cauliflower, and cabbage.
- Fish, liver, meat, eggs, and cereals (contain smaller amounts)