Vitamin K

A 1 cup serving of cooked collard greens contains 836 micrograms of vitamin K, which is significantly more than the 90 micrograms women need each day and the 120 micrograms men require. The primary job of vitamin K is to clot your blood when you injure yourself. You also need plenty of vitamin K for the health of your bones. The vitamin enables your body to use calcium properly, which helps maintain bone mass and might reduce your risk of osteoporosis.