Vitamin K1, also known as phylloquinone, is one of the two primary forms of vitamin K, along with vitamin K2 (menaquinone). It is a fat-soluble vitamin that plays a crucial role in blood clotting (coagulation) and bone health.
Key points:
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Dietary Source: Pimarily found in green leafy vegetables, such as kale, spinach, broccoli, cabbage, and lettuce. It is also present in smaller amounts in other plant foods, such as soybeans, green tea, and certain vegetable oils (e.g., canola oil, soybean oil).
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Function: Essential for the synthesis of clotting factors in the liver, particularly prothrombin (also known as factor II), which is necessary for blood clot formation.
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Recommended dietary allowance: 90 micrograms (mcg) per day for women and 120 mcg per day for men.
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Safety: Deficiency is rare but can occur in individuals with malabsorption disorders or liver disease. Symptoms may include easy bruising, excessive bleeding, and impaired bone health. Toxicity is rare and typically occurs with high-dose supplementation; this can interfere with anticoagulant medications and may lead to blood clot formation.