Vitamin K is a fat-soluble vitamin. Fat-soluble vitamins are stored in the body’s fatty tissue and in the liver. Vitamin K is known for its important function in the formation of blood clots or coagulation (the word K is derived from the German word “Koagulationsvitamin”). Vitamin K works synergistically with other minerals and vitamins, like calcium and vitamin D, to promote bone health. Prothrombin time (PT)/ International Normalized Ratio (INR) is typically used to monitor the administration or levels of vitamin K. This test measures the presence of vitamin K-dependent factors, which is required for managing patients with warfarin toxicity or coagulopathies (bleeding disorders) due to vitamin K.
Insights into Vitamin K Deficiency
Vitamin K deficiencies are usually diagnosed when patients experience unexplained or excessive bleeding or easy bruising. The most common test to investigate bleeding is the prothrombin time (PT) test. If prothrombin time is longer than normal and low levels of vitamin K are suspected, then vitamin K is given either orally or through injections. If the bleeding stops and PT/INR results return to normal, then it can be assumed that it was due to a deficiency in vitamin K.
The occurrence of vitamin K deficiency is quite rare because it is found in abundance in leafy green foods and can also be synthesized by intestinal bacteria. Sometimes, the use of antibiotics can kill these bacteria resulting in a mild deficiency, particularly in individuals with pre-existing low vitamin K levels. A vitamin K deficiency can lead to uncontrollable bleeding. Other possible causes of vitamin K deficiencies are:
- Certain illnesses that inhibit the absorption of vitamin K such as gallbladder or biliary diseases, cystic fibrosis, celiac disease (gluten intolerance), Crohn’s disease (inflammatory bowel disease), and liver disease.
- Use of anticoagulants such as warfarin.
- Long-term haemodialysis.
- Severe burns.
Importance of Vitamin K for Overall Well-being
Vitamin K is used to lower the risk of bleeding, particularly in individuals with liver disease, conditions where individuals have difficulty absorbing this vitamin, or those on prolonged antibiotic therapy. This vitamin is necessary for your body to use calcium effectively in bone development. Higher vitamin K intakes were linked with higher bone density, while low vitamin K levels were linked to lower bone density or an increased risk of fractures. In addition, low vitamin K levels have been associated with osteoarthritis, a common condition in which there is progressive loss of cartilage from the joints. There is growing evidence that vitamin K may play an important role in bone health.
Dietary Sources of Vitamin K
Foods that are high in vitamin K include liver, green tea, broccoli, turnip greens, kale, cabbage, spinach, and dark green lettuce. The green pigmentation observed in these plants is due to chlorophyll, which plays a role in the formation of vitamin K.
For people aged 20 and older, the average daily recommended amounts of vitamin K from food sources are 122 micrograms (mcg) for women and 138 mcg for men. When both food and supplements are included, women’s intake rises to 164 mcg and men’s to 182 mcg.
Preparation and General Instructions
No special preparations are required to undergo the prothrombin time test. Please inform your healthcare provider if you are taking any supplements or medications. A medical technician will draw your blood by inserting a small needle into a vein in your arm. This sample will then be sent to a laboratory to determine the prothrombin time. It is common to experience some pain or discomfort at the site where the needle was inserted; however, this discomfort typically subsides over time.
Interpretation of Test Results
The vitamin K test result will show whether you have a deficiency or excess vitamin K. The normal range for vitamin K in the blood is 0.2–3.2 nanograms (ng) per milliliter. A level that is lower than normal means you could be deficient, which may require you to take some supplements.
The prothrombin time (PT/INR) test is conducted to determine the time it takes for a clot to develop in a blood sample.
Prothrombin time is usually reported in seconds; however, for those who are on warfarin, the results will be reported in terms of the International Normalized Ratio (INR).
The normal results can vary based on the use of warfarin in individuals.
|
People who do not take warfarin |
INR 0.8 – 1.1 |
|
People who take warfarin |
INR 2.0 – 3.0 |
|
In seconds |
11 – 13.5 seconds |
Prothrombin time in seconds (for individuals who do not take warfarin):
- Higher than normal measurements might reflect a delay in the blood's clotting process.
- Lower than normal measurements may be an indication of blood clotting more quickly than expected.
- Abnormal clotting times can result from insufficient vitamin K, which is vital for blood clotting, liver conditions, or a deficiency in the factors that help with coagulation.
Prothrombin time in INR (for individuals who take warfarin):
- Low levels of INR values (<2.0) may mean that your blood is clotting more quickly than normal, and you may be at risk for dangerous blood clots.
- Elevated INR levels (>3.0) could indicate that your blood is clotting more slowly than usual, putting you at a higher risk of bleeding.
Water-soluble chlorophyll is the most common form of vitamin K that you can get over the counter. It comes in many different forms, including tablets, capsules, and liquid. However, because of the risk of side effects and interactions with other medications, dietary supplements should be taken only under the supervision of a healthcare provider.
Vitamin K is a necessary nutrient that supports the overall functioning of the body. It needs to be incorporated into our diet, either through foods or supplements. Vitamin K deficiency can cause serious complications, so it is essential that individuals regularly consume vitamin K-rich foods.
