The vitamin K belongs to the group of fat-soluble vitamins. K comes from the German word for coagulation which refers to the process of blood clotting, because vitamin K is essential for the function of certain proteins involved in blood clotting. The only biological role of the vitamin K is as a cofactor for enzymes that catalyze the carboxylation of the amino acids, particularly glutaric acid, resulting in conversion to the gamma-carboxyglutaric acid. This process is essential for calcium binding to specific proteins.

There are 5 types of vitamins K:

К1 - Fitomenadion, Menahinon, Phylloquinon, Fitonadion and Mefiton

К2 - Farmohinon

К3 - Menadion

К4 - Menadiolis acetas

К5 - Metiloksiaminonaftalin

Where can you find the vitamin K?

Vitamin K is found mostly in the leaves of horse chestnut, spinach, nettle, cabbage, cauliflower, pumpkin, tomatoes, strawberries, carrots, and in smaller amounts in other plants.

Animal products contain very little amounts of vitamin K. In the human body, the vitamin K is produced in the intestines of intestinal bacteria.

Vitamin K2 is found in the yolk of chicken eggs, butter, veal liver, different cheeses and products made from fermented soy beans.

Enemies of the vitamin K are the aspirin and radiation, as well as heat treatment on the food.

In its natural form, the vitamin K is not toxic, but overdosing with Menadion is not recommended.

Recommended dose of the vitamin K

Recommended dose of the vitamin K for a 25 year old man is 120 mgr per day, and for elderly woman 90 mgr daily. Children until the age of 7 – should take around 10 to 20 mgr. daily.
For children above 7 and teenagers – recommended dose is 15 to 100 mgr daily.

Vitamin K and coagulation

The vitamin K is very important for synthesis of the coagulation factor in the liver. The vitamin K is essential for creating prothrombin - which helps for blood clotting. 

Patients on anticoagulant therapy should avoid food rich with vitamin K. Elderly people who are on antibiotic therapy for a longer period have increased needs for vitamin K. Also, there are some factors that can increase the need for vitamin K like consuming some drugs, illnesses which affect the absorption and availability of this vitamin. The vitamin K helps in prevention of inner bleeding and big menstrual bleeding.

Vitamin K for stronger bones

Vitamin K is great for the bones, because it helps the proteins, which are composing part of the bones, to maintain their proper functioning. People who take 250µg vitamin K daily, prevent the risk of bone fracturing. The best recommended dose of vitamin K is 90 to 120µg daily

Vitamin K - Essential for newborn babies

Newborn babies are not able to produce this vitamin in their intestines and mothers milk is very poor with vitamin K. Therefore, it’s strongly recommended for them to take additional amounts of vitamin K. Reduced absorption of fat in the digestive tract can cause lack of vitamin K. If there is lack of vitamin K in mother`s placenta ( specially if the pregnant woman is taking anticoagulants) it’s possible to reverse skeleton malformations to the newborn. There are medications that reduce the absorption and availability of this vitamin like: antibiotics, sulfa-medication, anticonvulsants, as well as phenolbarbitol. Anticonvulsants, if used in pregnancy, can cause lack of vitamin K to the newborn babies and prolong bleeding. Wafarin, a drug prescribed against the creation of clots when there is a risk of thrombosis, is not supposed to be given during pregnancy because it can cause disturbances in the development of the fetus. The use of wafarin in the first three months of the pregnancy can cause obstacles in bone development. Doctors advise that the minimum daily dose that prevents the deficit is one microgram of vitamin K of one kilogram of body weight. The same amount is recommended for children, and infant about five micrograms a day.

Vitamin K and “eye bags”

This vitamin is effective against the “eye bags”, so dermatologists recommend putting it on the skin before sleeping. Also, the vitamin K is good against losing skin color under the eyes. The vitamin K through the pores and reaches the damaged arteries which helps in blood clotting. That’s how it prevents the creation of dark “eye bags”, and helps the tissue quickly healing.

Vitamin K and Alzheimer’s disease

Studies on the antioxidant characteristics of vitamin K show that the concentration of vitamin K is smaller in the circulation of holders APOE4 gene, and recent studies indicate the capacity of inhibiting the death of nerve cells due to oxidative stress. It is possible that vitamin K can reduce the damage to nerve cells and its further using may benefit in treating Alzheimer's disease, but more researches are necessary in this field