Why you need it
Vitamin K, a fat-soluble vitamin, gets its name from the German word koagulation, which refers to this vitamin's critical role in normal blood clotting. Two noted research initiatives -- the Nurses' Health Study and the Framingham Heart Study -- suggest that vitamin K may also help maintain strong, healthy bones.
Researchers at the University of Toronto are testing the ability of vitamin K to maintain or increase bone density in postmenopausal women with osteopenia, a condition that precedes osteoporosis. The researchers are looking for volunteers for the study.
How much you need
Check recommended daily intake chart.
Why you might not be getting enough
Although a vitamin K deficiency is uncommon in healthy adults, eating foods high in hydrogenated or trans fats -- such as baked goods, cookies and many fast foods -- may decrease the amount of vitamin K that is available to your bones, say researchers at Tufts University in Boston.
Vitamin K deficiency can cause impaired blood clotting. Symptoms can include easy bruising and uncontrolled bleeding in the form of nosebleeds, bleeding gums, blood in the urine or stool, or extremely heavy menstrual bleeding. Some newborn infants are more at risk because their immature intestinal tracts may not have enough bacteria to produce this vitamin.
In Canada, vitamin K supplements are not available over the counter, and vitamin K is not found in over-the-counter multivitamins.
Are you getting too much?
Too much vitamin K may interfere with the effects of blood-thinning medications, such as warfarin (Coumadin) and heparin. If you are taking one of these medications, it is wise to moderate your intake of foods that are rich in vitamin K.
The best foods for vitamin K
Much of the vitamin K you need comes from “friendly&" bacteria that live in your intestines. You can get the rest from a variety of foods. The best food sources are romaine lettuce, spinach, kale and other leafy green vegetables; broccoli; cabbage; green peas; brussels sprouts; and beef liver. There is also some vitamin K found in plant oils, such as soybean, canola and olive oils, as well as in egg yolks and dairy products. Here are some dietary sources of vitamin K.
1/2 cup (125 mL) boiled spinach - 360 mcg
1/2 cup (125 mL) boiled broccoli - 113 mcg
2/3 cup (150 mL) boiled cabbage - 98 mcg
1 tbsp (15 mL) soybean oil - 26 mcg
1/2 cup (125 mL) boiled green peas - 23 mcg
1 tbsp (15 mL) canola oil - 20 mcg
Try one of our recipes rich in vitamin K:
Garlic Spinach and Peppers
Ragout of Lamb with Spinach and Rice
Spiced Spinach Omelette
Creamy Noodles with Chicken and Broccoli
Wild Rice and Broccoli Casserole
Curried Potatoes and Peas
Spinach and Green Pea Pasta