Vitamin K is obtained from food, vitamin supplements and is manufactured in the intestines. The vitamin is essential for blood clotting and bone health. Low levels can lead to osteoporosis, especially in the elderly. Malabsorption syndrome, liver and gallbladder disease, kidney dialysis, use of blood thinners and a long-term need for antibiotics are the most common reasons for low levels of vitamin K.
Bacteria
Vitamin K-2, or menaquinone, is normally produced by bacteria in the large intestine. Deficiency of the vitamin is very rare and occurs when vitamin K cannot be absorbed from the intestines. Symptoms of low levels include easy bruising and bleeding.
Vegetable Sources
Green vegetables, including spinach, kale, broccoli, asparagus and Brussels sprouts are rich in vitamin K. Other vegetables that are sources of vitamin K include Swiss chard and mustard greens. The daily recommended intake of vitamin K is 120 micrograms a day, according to the "Council for Responsible Nutrition".
Vitamin K Fruits
Commonly consumed fruits are low in vitamin K, with the exception of green apples. The University of North Carolina, Chapel Hill categorizes a small green apple as having medium amounts of the vitamin. An apple that weighs 100 grams contains 60 micrograms of vitamin K -- which is one-half of the recommended daily intake.
Oils
Oils with higher levels of vitamin K include olive oil, margarine and soybean oil. Adding margarines and oil to foods easily adds up to adequate intake of the vitamin that can ensure balance, absorption of other nutrients and optimal bone and vascular health.
Supplements
Most multi vitamins contain vitamin K, but in small amounts. Patients on blood thinners are advised to avoid high doses of vitamin K as it can reverse the effects of warfarin used to prevent blood clots; however, these patients should still discuss taking multi vitamins with their doctors before consuming them. According to the National Academies, there have been no reports of toxicity from high intakes of vitamin K, but data is limited.
References
- University of Maryland Medical Center; Vitamin K; June 18, 2009
- Medline Plus; Vitamin K; March 7, 2009
- NIH; Coumadin and vitamin K; March 2003
- University of North Carolina: Vitamin K Foods
- National Academies: Dietary Reference for Vitamins
- Council for Responsible Nutrition: Vitamin and Mineral Recommendations
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