Vitamin K belongs to the group of fat-soluble vitamins, which are absorbed into the body by means of dietary fat; they can also be stored in fat cells and liver tissues. The K in vitamin K comes from the vitamin's German name, "Koagulationsvitamin." Vitamin K exists in two major forms: phylloquinone, the primary source of vitamin K in your diet, and menaquinone, which is synthesized by bacteria in the digestive tract.
Functions
Vitamin K is notable for its role as a coagulation factor; it is a significant factor in a series of reactions that allow your blood to clot normally. Without vitamin K, a small cut would cause uncontrollable bleeding and severe blood loss. Because of this role, vitamin K is often referred to as the clotting vitamin. Vitamin K also plays an important role in proper mineralization of your bones. Three proteins -- osteocalcin, protein S and matrix Gla protein -- contribute to the strength of your bones and rely on vitamin K to function.
Daily Recommendations
The Food and Nutrition Board provides daily recommendations for vitamin K as an adequate intake, or AI, which represents the approximate amount needed daily, by an individual of a certain age and sex, to stay healthy. For children and teenagers, the AI differs only by age. Children between 1 and 3 need 30 mcg per day; those between 4 and 8 require 55 mcg daily. Children between 9 and 13 should consume 60 mcg per day; teenagers between 14 and 18 require 75 mcg daily. After the age of 18, needs for vitamin K differ based on sex. Men aged 19 and older need 120 mcg a day; women of the same age need 90 mcg daily.
Food Sources
Although it is tempting to use multivitamins to meet your vitamin needs, you benefit more by meeting your vitamin K intake through diet. Increasing your intake of leafy green vegetables, especially kale, spinach, lettuce, Swiss chard and broccoli, can help you meet your goals. Augmenting your diet with vegetable oils, such as olive oil, soybean oil and canola oil, and oil-rich foods, such as mayonnaise, can help you to meet your vitamin K needs.
Considerations
The bacteria that normally live in your digestive tract synthesize significant amounts of vitamin K in the form of menaquinone. Because the exact amount of vitamin K that your body can make is unknown, the AI for the vitamin is based only on your dietary intake.
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