The real special K is not a breakfast cereal, but a vitamin.
Vitamin K affects everything from blood clotting to calcium absorption. Some scientists even believe it fights cancer. Vitamin K has several types: vitamin K1, found in plants; vitamin K2, created by bacteria in your intestines; and vitamins K3, K4 and K5, which are synthetic.
Why do we need it?
Without vitamin K, the blood loss from a paper cut could be on par with a knife wound. Vitamin K also plays a part in bone mineralization and stopping osteoporosis. A Belgian study, first published in the European Journal of Medicinal Chemistry, even showed vitamin K to help destroy cancer cells.
Where can we find it?
If it's green, there's a good chance it's packed with vitamin K. Leafy green vegetables all have high levels of vitamin K, according to the USDA. You also can find it in certain vegetable oils, such as olive and canola. Soybeans and soy products are also very high in vitamin K. Vitamin K is a fat-soluble vitamin, meaning that it is better absorbed with fat -- so drizzle your broccoli with a little olive oil, and you'll be a vitamin K powerhouse.
How much do we need?
The USDA recommends at least 120 micrograms of vitamin K per day for men, 90 micrograms for women and 60 micrograms for children. However, the National Institutes of Health warns that people taking blood-thinners such as Warfarin might need to monitor their vitamin K intake and consult their doctors.