Vitamins are essential nutrients. Even if we only need small amounts of them the body is not able to produce enough of all of them. In this article we will focus on vitamin K. The K comes from the German word for coagulation. It was discovered by the Danish biochemist Henrik Dam in 1934, which he received the Nobel prize for in 1943. Vitamin K has several important functions.
Vitamin K1, Fyllokinon (natural)- dissolves in fat
Vitamin K2, Manakinon (natural) – dissolves in fat
Vitamin K3, Menadion (artificial) – dissolves in water
Vitamin K1 can be found in green vegetables such as broccoli, spinach, lettuce, parsley and cabbage, as well as peas, avocados, carrots, cheese, butter, eggs, potatoes, fruit and berries. This vitamin can also be found in olive oil, soya oil and rapeseed oil. Only 5-10% of vitamin K1 is taken up in the blood together with fat from food. Thereafter it is converted to vitamin K2, this happens preferably in the liver. K2 is formed by bacteria in the large intestine, but in smaller amounts than previously assumed. Margarine and other hydrogenated vegetable fats (hydrogenated oil) may reduce absorption and the biological effect of vitamin K2. A dish that contains lots of vitamin K2 is “Natto” (steamed and fermented soybeans), which is a traditional Japanese breakfast and “samurai food”. This is said to play a significant role for Japan’s high average life expectancy.
Vitamin K2 is necessary for the blood’s coagulation. It happens with the help of several activating enzyme reactions, which also can bind calcium.
K2’s function in the skeleton happens with the help of the following enzymes: osteocalcin, Matrix Gla protein, Protein S and Gas6.
Osteocalcin is formed in bone-forming cells, osteoblasts, and is necessary for their function. The protein is regulated by vitamin D3. Osteocalcin can also be found in the brain. If there is not enough osteocalcin in the brain, the brain cells become more exposed to the effects of calcium.
An enzyme reaction called gamma-carboxylation is necessary for the mineral binding, the mineralization of the skeleton. Too little carboxylation, under carboxylation, can increase the risk of osteoporosis and bone fractures. Vitamin K2 and D3 counteracts under carboxylation of osteocalcin (ucOC). Matrix Gla protein (MGP) promotes growth and development of bone tissue. MHP also prevents the deposition of calcium in soft tissues (such as arteries with arteriosclerosis) and cartilage (osteoarthritis).
K2 deficiency can be found in all ages. It is important that the mother consumes vitamin K2 and K1 during her pregnancy. There is only a small amount of vitamin K in breast milk.
Hunger and fasting for several days can lead to a lack of K2, as it is only deposited for a few days. Lack of pro-bacteria (healthy intestinal microflora), caused by for example treatment with antibiotics, reduces the intestinal bacteria’s production of vitamin K. A modern lifestyle with an unhealthy diet can also lead to a lack of vitamin K.
The importance of vitamin K in the prevention of bone fractures is enlightened in studies such as Nurses Health Study, which showed that people who have a low consumption of vitamin K1 had a 30% higher chance of fracturing a bone. However, in the Framingham study no connection was found between K1 from the diet and bone density (BMD), bone strength and risk of bone fractures. On the other hand, it is proved in scientific studies that vitamin K2 reduces the risk of bone loss and fractures. Especially when taken in combination with calcium and vitamin D3. There are few incidences of osteoporosis in Japan, where they ingest high amounts of K2 through their Natto-dish. Vitamin K2 can also prevent kidney stones by normalizing the calcium metabolism.
Vitamin K2 is a powerful antioxidant and can counteract inflammation. Natto - the traditional Japanese breakfast is made of fermented soybeans and is naturally rich with vitamin K2. However, before you start running to the nearest health food store, you should know that Natto has a slimy consistency and a distinctive, strong odor, which tends to make some curl their nose.
Vitamin K2 is far more effective than vitamin K1 with regards to reducing the risk of cardiovascular diseases. Amongst other studies, the famous Rotterdam study showed that the risk of death caused by blood clots is halved when consuming vitamin K2. Matrix Gla Protein (MGP) is the protein that to the greatest extent prevents atherosclerosis of soft tissue and this protein is dependent on vitamin K2. It protects especially the elastic fibres in the blood vessels against calcification. When the elasticity of the blood vessels is reduced, the risk of high blood pressure increases. Vitamin K2 can even reduce already formed calcification in the blood vessels. It is also proven that a supplement of vitamin E in the form of tocotrienol and garlic can have the same effect. It can be common with a magnesium deficiency, which will prevent uptake of calcium. Vitamin K2 is necessary to incorporate calcium in the bone tissue and to ensure that it does not end up in the cardiovascular system. This is also true for vitamin D3, which most people have too little of in the blood, especially during the winter.
The recommended daily dose of vitamin K2 is 90 micrograms for women and 120 micrograms for men.
