Vitamin K is a fat soluble vitamin. Its main functions are to facilitate blood clotting and to synthesize necessary proteins in kidneys, blood and bone. In addition, this vitamin also promotes the binding of calcium to the bone to promote stronger bone development and prevent osteoporosis.
The recommended dosage is 150mcg daily for adults. Too much vitamin K can lead to sweating and flushing. It may also contradict the effect of blood thinning drug.
Although human body can produce vitamin K, it is still necessary to rely on external source to fulfill the daily requirement. K1 and K2 are the natural form and they are not toxic to the body. K3 is the synthetic form and can cause harm. There are abundant sources of food containing the natural form of this vitamin. Some green leafy vegetables and fruits are the primary food sources.
Spinach, okra, kale, mustard greens, turnip greens, collards are the vegetables with the highest in vitamin k content. However, the vitamin content varies in accordance to the ways the vegetables are being kept and prepared. Frozen and cooked kale has higher content then fresh cooked kale.
On the other hand, some vegetables contain zero amount of vitamin K. They are canned yellow sweet corn, cream-style yellow sweet corn and canned beets. Some fruits also contain no value of this vitamin, which are startfruit, lemons, oranges, tangerine and white grapefruit. However, it does not mean that these vegetables and fruits do not have any nutritional value. Take corn as an example, it contains high value of beta-carotene and small amount of vitamin B and C. Moreover, it is also rich in protein and fiber. It is just not being the right food source to fulfill the vitamin K daily requirement.
It is important for those taking anti-clotting drug to include vegetables with no or low value of this vitamin to avoid the nutrient drug interaction. Cabbage, asparagus, lettuce, broccoli, celery, cucumber are all those vegetable having very low vitamin K content.