Can Leafy Greens Cause Blood Clots?
On the Internet, you can often find comments warning that green leafy vegetables, rich in vitamin K, are contraindicated for people prone to blood clots. Such comments usually refer to parsley, celery, spinach, various types of cabbage, and other foods high in vitamin K.
These comments suggest that eating such foods can lead to thrombosis, which can lead to dangerous diseases such as pulmonary embolism, heart attack and stroke. However, these warnings are not true. Vitamin K, which is found in green leafy vegetables and other foods, does help blood clotting, but that does not mean that consuming it can lead to thrombosis.
In fact, vitamin K helps control blood clotting and can prevent thrombosis and other dangerous diseases. Some people have begun to avoid certain foods because they have been warned that they are harmful. However, this approach can cause us to miss out on getting the good stuff from these foods. Today we will look at where this idea came from and why it is wrong. We will also look at the scientific evidence that shows that these foods can be consumed without harming your health.
Effect of Vitamin K on Blood Clotting and Risk of Blood Clots
You can come across articles on the internet from unverified and unknown doctors who may warn against eating certain foods if you are prone to blood clots. Some of them may claim that eating certain foods can cause an excess of vitamin K and lead to harm to health. However, despite these articles, the mechanisms of blood clotting remain the same.
The clotting process can be caused by damage to the vascular wall or by internal factors that are released into the bloodstream as a result of injury. But regardless of which mechanism triggers coagulation, it eventually leads to the conversion of prothrombin to thrombin and the formation of a blood clot.
Prothrombin is an important protein found in blood plasma and is the No. 2 clotting factor. During a cascade of coagulation reactions, prothrombin is converted into its active form, thrombin. Thrombin acts on another protein, fibrinogen, converting it to its polymeric form, fibrin, which forms long threads that are intertwined with each other.
Fibrin threads come into contact with platelets at special sites where there are glycoproteins on the surface of platelets, which serve as contact sites for fibrin threads. Thus, a network of platelets and fibrin is formed, which attaches to the walls of blood vessels and creates a trap for red blood cells – red blood cells with a diameter of about 7 microns. The red blood cells are unable to penetrate this mesh, resulting in the formation of a blood clot.
Looking at the table that describes the clotting factors, you can see that some of them depend on the presence of vitamin K. For example, the already mentioned prothrombin (clotting factor #2), proconvertin (clotting factor #7), Christmas factor (factor #9) and factor #10 (Stuart-Prower factor), which are affected by drugs like Xarelto. Vitamin K affects the activity of these very components of the clotting cascade, not their amounts, which are programmed genetically.
It is important to note that vitamin K deficiency is not the cause of a deficiency of these clotting factors. For example, people with hemophilia may simply be deficient in a particular clotting factor, but vitamin K does not play a role in this case. However, its absence or deficiency makes these factors inactive. Based on the action of vitamin K on the activation of clotting factors is based on the action of the drug warfarin.
How Anticoagulants Work and Why They Are Prescribed?
Warfarin is a vitamin K antagonist and is used to reduce the activity of vitamin K-dependent clotting factors. When vitamin K loses its activity, other clotting factors also lose activity. This leads to a state of hypocoagulation, where the blood cannot form a clot as quickly as necessary.
Warfarin and similar anticoagulants are used in cases of increased risk of thrombosis, which may be caused by external or internal factors. For example, in people with a standing mechanical heart valve, thrombus formation may be caused by a foreign surface for blood flow. Also in people with atrial fibrillation, the distended atrium does not contract, causing atrial fibrillation, blood stasis, and activation of internal clotting factors, which triggers the clotting cascade.
Anticoagulants may be prescribed for various thrombotic conditions, such as deep venous thrombosis and disseminated intravascular clotting syndrome, which may result from various pathological processes in the body, including severe forms of COVID-19 with cytokine storm. In such cases, anticoagulants can help prevent blood clots and prevent complications such as pulmonary embolism, stroke, or heart attack.
Warfarin and other anticoagulants can help prevent thrombosis in such cases. However, it is important to remember that anticoagulants can cause bleeding, so their use should be supervised by a doctor. In addition, when taking warfarin and similar drugs, it is necessary to monitor the level of vitamin K in the diet to avoid unwanted interactions between the drug and food.
Note that vitamin K is not mentioned anywhere in lists of factors that cause increased blood clotting. Many other factors can be found on such lists, including calcium, but calcium is never blamed for causing clotting, although it is impossible without it. Blood used for laboratory tests is decalcified to stop blood clotting and to perform tests.
Some doctors are wary of eating greens that contain vitamin K because they have studied the subject in their schools. Doctors who prescribe anticoagulants such as warfarin use the logic that if we remove vitamin K from a patient’s blood, it will reduce blood clotting, and if we add vitamin K, it will increase the tendency to clot.
This may be correct for patients who are taking warfarin, but only if they are not taking too much vitamin K. Warfarin is prescribed for people who are prone to thrombosis, and if we give vitamin K along with warfarin, the effects of warfarin may be diminished. However, vitamin K itself will never lead to thrombosis.
Conclusion
In conclusion, it is safe to say that concerns about eating greens containing vitamin K are unfounded. The U.S. National Institutes of Health guidelines do not indicate an established toxic dose of vitamin K, and they describe no cases of adverse health effects of high doses of vitamin K from food.
To date, there have been no scientific studies done to all standards proving that eating greens such as parsley or any other greens can cause an increased tendency to clots. Therefore, it is safe to say that eating greens containing vitamin K is not a health risk and should be included in the diet as a source of valuable nutrients.