Vitamin K1 - phylloquinone

​Function: 
Vitamin K1 is needed for blood clotting. 

Deficiency: 
Vitamin K1 deficiency is rare and leads to poor blood clotting.  A severe deficiency is associated with hemorrhage. 

Absorption:
Vitamin K1 is a fat-soluble vitamin, meaning that it must be consumed with fat in order to be absorbed.  Supplementation of Vitamins A and E may interfere with Vitamin K1 absorption and utilization.
 
Sources:
Excellent sources of Vitamin K1 include broccoli, kale, Swiss chard, turnip watercress greens, collards, spinach, salad greens, cabbage, Brussels sprouts, and mustard greens.  Additional sources include asparagus, celery, green beans, avocado, kiwi, pumpkin, peas, peanut butter, lentils, kidney beans, pinto beans, soybeans, and brewed coffee.  Vitamin K1 may be destroyed when exposed to light. 

Toxicity:
The synthetic version of Vitamin K (menadione) has been associated with liver damage. Self-supplementation is NOT recommended.

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* This information is not intended to encourage self-supplementation.   As you will read in individual nutrient content, self-supplementation can be unnecessary or even dangerous.  I highly recommend micro-nutrient blood testing before choosing to take any supplements that are not whole-foods based.
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References:
Gropper SS, Smith JL, Groff JL. Advanced nutrition and human metabolism. 5th ed. Belmont, CA: Wadsworth; 2009.
Mahan L, Escott-Stump S, Raymond J. Krauses's food and the nutrition care process. 13th ed. St. Louis, Missouri: Elsevier Saunders; 2012.