Vitamin K isfat-soluble vitaminthat plays a role in blood clotting in the body.
It comes in two forms: vitamin K1 (phylloquinone) and vitamin K2 (menaquinones).
Vitamin K1 is naturally found in some foods, such asgreen vegetableslike collard greens,spinach, and broccoli.
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Vitamin K is also available as a dietary supplement.
However, most people get the amount of vitamin K they need through diet alone.
That means some supplement products may not contain what the label says.
No supplement is intended to treat, cure, or prevent disease.
Vitamin K therapy has been used to reverse the effects ofanticoagulants (blood thinners).
An example of this may be someone prescribed anticoagulants who suddenly requires emergency surgery.
Vitamin K has a role in the formation of a protein called matrix Gla-protein (MGP).
However, it is still unclear whether supplementing vitamin K can slow vascular calcification.
Newborns are routinely given a standard vitamin K injection right after birth to prevent deficiency.
This is because:
In adults, vitamin K deficiency is most often related to malabsorption disorders.
A vitamin K deficiency can occur from inadequate intake or poor absorption in the gastrointestinal (GI) tract.
Most people get enough vitamin K in their diets.
Poor absorption may also be a side effect of some medications.
How Do I Know If I Have a Vitamin K Deficiency?
Vitamin K status can be evaluated by assessing dietary intake and absorption.
If you have a GI condition or fat malabsorption, you are at greater risk of vitamin K deficiency.
Symptoms of malabsorption include frequent diarrhea, light-colored stools, and weight loss.
In those prescribed anticoagulants, prothrombin times are routinely assessed to monitor the effectiveness of anticoagulant dosing.
What Are the Side Effects of Vitamin K?
Taking vitamin K with blood thinners can make the medication less effective.
Antibiotic use may block the action of and reduce vitamin K status in the body.
Adding more vitamin K to your usual intake will make the medications less effective.
It is important to keep your vitamin K intake consistent.
Dosage: How Much Vitamin K Should I Take?
Most people can meet their vitamin K needs through diet alone.
For supplementation, dosing can vary depending on the cause of the deficiency.
At birth, newborns routinely receive a 0.5 to 1 mg vitamin K intramuscular injection to prevent a deficiency.
Note that the AI for vitamin K is provided in micrograms (mcg).
Some dosing suggestions for vitamin K are in milligrams.
For conversion, 1 mg equals 1,000 mcg.
When looking at supplements, it is important to look at the amounts and units of measure.
What Happens If I Take Too Much Vitamin K?
There are no known adverse events associated with excess vitamin K intake.
It is also available as a single nutrient supplement and in multivitamin products.
The amount of vitamin K in multivitamin products is usually less than 75% of the daily value.
It is easy to get adequate amounts of vitamin K through the diet, and a deficiency is rare.
Certain fat malabsorption disorders may put you at higher risk of a deficiency.
Vitamin K functions to help with blood clotting.
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