Vitamin K

Overview

Vitamin K is a fat-soluble vitamin essential for blood clotting and bone health. It is named after the German word for coagulation, Koagulationsvitamin. Vitamin K plays a crucial role in the synthesis of proteins involved in blood clotting and bone metabolism^[1]. Historically, vitamin K was first identified in the early 20th century when it was discovered that chicks fed a diet lacking in certain fats developed bleeding disorders^[2].

Forms and Variations

Vitamin K exists in two main natural forms: Vitamin K1 (phylloquinone) and Vitamin K2 (menaquinone). Vitamin K1 is primarily found in green leafy vegetables and is involved in photosynthesis^[1]. Vitamin K2, particularly menaquinone-4 (MK-4) and menaquinone-7 (MK-7), is found in animal products and fermented foods. Vitamin K3 (menadione) is a synthetic form but is not used in human nutrition due to its toxicity^[1].

Dosage and Administration

The recommended daily intake of vitamin K varies by age. For adults, the Adequate Intake (AI) is 120 mcg/day for men and 90 mcg/day for women^[2]. Vitamin K supplements are best taken with fat to enhance absorption, as it is a fat-soluble vitamin^[3].

Scientific Research and Mechanism of Action

Vitamin K acts as a coenzyme for the enzyme gamma-glutamyl carboxylase, which modifies proteins to bind calcium ions, essential for blood clotting and bone health^[1]. Research suggests that vitamin K may help reduce the risk of fractures and improve bone density, though results are mixed^[3]. Vitamin K also plays a role in preventing arterial calcification by activating matrix Gla protein^[1].

Benefits and Potential Uses

Vitamin K is crucial for blood clotting and bone health. It may also help prevent cardiovascular diseases by reducing arterial calcification^[1]. Additionally, vitamin K is used to prevent bleeding in newborns and in patients with liver disease or those taking anticoagulants^[4].

Side Effects and Risks

Generally, vitamin K is safe with minimal side effects. However, high doses of synthetic vitamin K3 can be toxic^[1]. Natural forms of vitamin K1 and K2 are considered safe for most people.

Interactions and Precautions

Vitamin K can interact with anticoagulant medications like warfarin, reducing their effectiveness^[3]. Individuals on these medications should maintain consistent vitamin K intake. Pregnant and breastfeeding women should consult healthcare providers before taking supplements^[2].

Impact on Biomarkers

Vitamin K affects the levels of clotting factors in the blood, such as prothrombin time (PT) and international normalized ratio (INR), which are used to monitor anticoagulation therapy^[3].

Overdose and Toxicity

There is no established Tolerable Upper Intake Level (UL) for vitamin K. However, excessive intake of synthetic forms like vitamin K3 can cause toxicity, while natural forms are generally safe^[1].

Disclaimer

The information provided in this document is for educational purposes only and does not constitute medical advice. It is essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.