The best food sources of vitamin K are green leafy vegetables such as cabbage, turnip greens, broccoli, lettuce, and spinach. Green tea is another good source with one cup giving you your daily requirement of this nutrient.
©2007 Publications International, Ltd.
Green vegetables such as broccoli are great sources of vitamin K
Not all of the vitamin K we get comes from the foods we eat. About one-third of our vitamin K comes from the bacteria living in our digestive tracts, which produce this vitamin as a by-product of their own metabolism. It used to be thought that intestinal bacteria produced about one-half of our vitamin K needs, but current findings indicate this was an overestimation.
Here is a chart you can use to find foods rich in vitamin K:
||Quantity|| Vitamin K (mg)|
|Lettuce|| 1/4 head
|Cabbage|| 2/3 cup
|Spinach|| 1/2 cup
|Asparagus|| 2/3 cup
|| 3 ounces
|Peas|| 2/3 cup
|Ham|| 3 ounces
For a long time, we didn't know enough about vitamin K to establish requirements. The first recommendation for the vitamin wasn't established until the 1989 edition of the RDAs.
The requirement varies by age; for men, it ranges from 75 to 120 mg as age increases from 11 to over 50 years. For women, the range is from 75 to 90 mg. A typical well-balanced diet in the United States supplies 300 to 500 mg of vitamin K -- more than enough to meet average dietary needs.
However, not every person meets the basic vitamin K requirements. In the next section, we'll discuss how even some healthy eaters with the best of intentions can become vitamin K deficient.
In addition to vitamin K, some other vitamins you might want to learn more about include:
- Vitamin A is the vitamin found in carrots that improves eyesight. Learn more about this key vitamin in How Vitamin A Works.
- Vitamin B3, also called niacin, assists other substances in the conversion of protein, carbohydrate and fat into energy. Learn more in How Vitamin B3 Works.
- How Vitamin C Works will show you how this vitamin can strengthen your immune system.
- Discovered only about 60 years ago, Biotin assists in several metabolic reactions. Learn more about it in How Biotin Works.
- Vitamin B12 has a a chemical structure much more complex than that of any other vitamin. Learn about this vitamin How Vitamin B12 Works.
- To learn about the many vitamins in our diet, how much you should be eating, and where to find them, go to our general Vitamins page. .