Vitamin K: What It Is, Where It Is Found, What Deficiency Leads To, and What It Does

Vitamins, which are essential micronutrients, play a key role in energy metabolism, immune functions, blood clotting, and many other bodily functions.

What is Vitamin K, What Are Its Types?

Vitamin K is a fat-soluble vitamin that is especially important for the process of blood clotting. Many proteins involved in clotting can only be produced in the presence of vitamin K. Therefore, a deficiency in this vitamin can make individuals more prone to bleeding. In addition to its role in clotting, vitamin K is also important for heart health and skeletal system health.

There are two main biological forms of vitamin K, referred to as K1 and K2. Vitamin K1, also known as phylloquinone, is the type of vitamin K produced by plants. During the photosynthesis process, which is responsible for the production of food and oxygen by plants, K1 vitamin plays a role. It is particularly abundant in green leafy vegetables such as spinach. K1 vitamin can remain active in the bodies of animals that consume these plants and participate in blood clotting pathways. K1 vitamin constitutes approximately 75-90% of the vitamin K consumed by humans.

Vitamin K2, in contrast to K1, is found in fermented products and animal-based foods. This vitamin can also be synthesized by beneficial bacteria living in the human digestive tract. Vitamin K2 has subtypes known as menaquinones, which are distinguished based on the length of their biochemical side chains. The main source of vitamin K2 for humans is the bacteria present in the intestines.

In addition to K1 and K2, there is also a synthetic form of vitamin K known as K3 (menadione). However, because this form can be toxic to animals, it has been removed from the treatment plans for vitamin K deficiency.

What Are the Symptoms of Vitamin K Deficiency?

Vitamin K primarily plays a role in the blood clotting process. If there is a deficiency, the production of proteins involved in clotting can be impaired, leading to an increased tendency to bleed excessively.

Vitamin K deficiency is more commonly observed in newborns. Due to its presence in many foods and its ability to be produced by bacteria in the digestive tract, vitamin K deficiency is rare in adults. Additionally, since it is fat-soluble, this vitamin can be stored in the body, and when intake from food decreases, the stored vitamin can be used to prevent deficiency. Despite these properties, vitamin K deficiency can still occur in the presence of certain health problems or the use of specific medications.

The primary symptom of vitamin K deficiency is excessive bleeding. This bleeding can occur not only at injury sites but also in any part of the body. Various signs and symptoms indicate an increased tendency to bleed:

• Easy bruising
• Small blood clots under the nails
• Bleeding in mucosal membranes inside the body
• Dark color in stools due to the presence of blood

When vitamin K deficiency occurs in newborns, the following symptoms may appear:

• Bleeding at the site of the umbilical cord cut
• Detection of bleeding under the skin or along the digestive tract
• Bleeding in the penis of circumcised babies after birth

In addition to these symptoms, a life-threatening condition called intracranial (brain) bleeding can also occur in newborns due to vitamin K deficiency, so careful monitoring is essential.

What Causes Vitamin K Deficiency?

The following conditions can increase the risk of vitamin K deficiency in adults:

• The use of blood thinners or anticoagulant medications, which interfere with vitamin K activity
• Long-term use of antibiotics that prevent vitamin K synthesis and absorption in the intestines
• A diet lacking foods rich in vitamin K
• Excessive intake of high doses of vitamin A or E

In addition to these factors, vitamin K deficiency can occur due to various health issues:

• Celiac disease
• Cystic fibrosis
• Disorders affecting the digestive system or bile ducts
• Removal of a portion of the intestine for various reasons

The following conditions may increase the risk of vitamin K deficiency in newborns:

• Maternal breast milk being low in vitamin K
• Incomplete transfer of vitamin K from the placenta to the baby during pregnancy
• The baby’s liver being underdeveloped and unable to use vitamin K effectively
• Lack of vitamin K2 production in the intestines during the first few days of life

How is Vitamin K Deficiency Treated?

The primary treatment for individuals diagnosed with vitamin K deficiency is to supplement the deficiency with external vitamin support. The most common approach is the prescription of oral K1 (phylloquinone) medications. For individuals with absorption issues in the digestive system, vitamin K treatment may also be administered through injections. The vitamin K dose for adults typically ranges from 1 to 25 milligrams. For some individuals taking anticoagulant medications, there may also be a need for vitamin K. In such cases, to prevent interactions between the medication and vitamin K, supplementation is generally given in lower doses.

In our country, to prevent potentially dangerous vitamin K deficiency in newborns, a prophylactic 1-milligram intramuscular vitamin K injection is given shortly after birth.

The recommended daily intake of vitamin K1 for adults is 120 micrograms for men and 90 micrograms for women. This amount can easily be achieved by adding a cup of spinach to a salad or consuming half a cup of vegetables such as Brussels sprouts or broccoli with dinner. 100 grams of raw spinach contains approximately 483 micrograms of vitamin K, which alone can fulfill up to four times the recommended daily intake. Here are the vitamin K contents in other foods, measured per 100 grams:

• Broccoli: 141 micrograms of vitamin K
• Brussels sprouts: 140 micrograms of vitamin K
• Liver: 106 micrograms of vitamin K
• Chicken: 60 micrograms of vitamin K

Due to the presence of vitamin K in many foods, deficiency is a rare condition. However, if it does occur, there is a risk of excessive bleeding, so it is advisable to remain aware of the symptoms.