Vitamin K is one of the fat-soluble vitamins that is necessary for normal blood clotting and bone strength. It is uncommon for a person to be deficient in vitamin K because there are a variety of dietary sources for vitamin K, and because the vitamin is produced by bacteria in the colon. Fruit green vegetables and common cooking oils can be a good source of vitamin K.
Vitamin K
Vitamin K is a fat-soluble vitamin that is stored in fat cells for use in times of dietary shortfall. Approximately half the body's normal daily requirement of vitamin K is obtained from dietary sources, and the other half is supplied by bacterial production in the lower intestine, according to Cancer.org. Vitamin K is necessary for normal production of blood clotting proteins in the liver and recently has been linked to production of the bone proteins that help prevent osteoporosis.
Daily Requirements
The recommended daily intake of vitamin K is 90 μg, or micrograms, for adult women and 120 μg for adult men, according to The University of Florida Institute of Food and Agricultural Sciences. Green vegetables are the best source of vitamin K. A single serving of turnip greens, spinach or broccoli contains more than the total daily requirement for an adult. Beef liver, green beans and canola cooking oil are also good sources of vitamin K, as well as some fruits.
Good Fruit Sources of Vitamin K
In the December 2003 issue of the "Journal of the American Dietetic Association", Mackenzie L. Dismore, et al. report on the vitamin K contents of many common fruits. Fruits with the highest content of vitamin K contain from 15 to 60 μg in each 100 g. These include dried prunes, kiwi, avocado, grapes and figs in decreasing order. Blackberries and blueberries contain the highest levels of the berries studied, with approximately 20 μg of vitamin K per 100 g.
Poor Fruit Sources of Vitamin K
Other fruits in the study had low levels of vitamin K, most with less than 5 μg per 100 g. Apples with peel attached, cantaloupe, honeydew melon, peaches, pears, cranberries and raspberries fall in this category. Citrus fruits, including oranges and pineapples, as well as bananas contain almost no vitamin K.
Supplemental Vitamin K
Most people who eat a balanced diet easily satisfy the daily requirement of vitamin K, according to the University of Maryland Medical Center. Some antibiotics, liver disease and malabsorption disorders such as celiac disease can lead to the need for supplementation. Multivitamins with vitamin K or vitamin K tablets are available. A health care provider should be consulted before beginning supplements, particularly if other medications, such as blood thinners, are being taken.
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