Vitamin K is a fat soluble vitamin which includes compounds with antihaemorrhagic properties with the generic name of naphthoquinones. The main representatives of this group are vitamer K1 or phyllochinon and vitamer K2 or menachinon. Both vitamers have an effect of a vitamin, whereas the bioactivity of K2 is approximately twice as weak as that of K1. In the organism, the synthetic menadione (vitamer K3) also becomes bioactive. Vitamer K2 is produced by the bacteria in the small intestine of the human organism, whereas vitamer K1 can be found in products of plant origin and fish oils. In the human organism, the main vitamer is K2.
Which foods contain the vitamin?
- Brussels sprouts
- Wheat germ
- Rapeseed oil
Biological functions of the vitamin
The main function of vitamin K is related to blood clotting. This coenzyme is needed for the synthesis/activation of different protein coagulation factors of the blood (prothrombin, factors VII, IX and X).
The vitamin also takes part in the mineralisation of bone tissue and plays an important role in the phospharylation of glucose.
A study conducted with 1,381 participants indicated that the level of vitamin K and inflammatory markers are inversely related in the organism, and the administration of vitamin K lowers the level of inflammatory markers for middle-aged and elderly people.
Additionally, it has been determined that the consumption of vitamin K also reduces the risk of coronary diseases and the risk of prostate cancer for men.
Absorption, storage and excretion
The vitamin is absorbed from the upper part of the small intestine and depends on bile acids and pancreatic lipase. Absorption is inhibited by mineral oils used as laxatives, dicoumarol, cephalosporins, aspirin and rancid fats.
The absorbed vitamin is stored in liver.
Vitamin K is excreted from the organism as sulphates and glucuronides.
Problems resulting from deficiency
The deficiency is improbable because the need for this vitamin is small and under normal circumstances, the intestinal microflora can guarantee sufficient synthesis.
- Slowdown of blood clotting
- Continuous nosebleeds
Risk groups for developing the deficiency
- Patients with vitamin K absorption disorders
- Chronic alcoholics
- Persons with continuous deficiency of food fats
- Patients with the deficiency of bile acids and lipase
- Patients with cystic fibrosis
- After long-term use of antibiotics
- Patients with the atrophy of small intestine mucosa
The first symptoms are perspiration and redness. Acute toxicity results in haemolytic anaemia, which is also followed by kernicterus in newborns.
Vitamin K is contraindicated for patients with the deficiency of glucose-6-P dehydrogenase, who have haemolytic anaemia.
Use of vitamin preparations
May be used as an additional treatment component for treating haemorrhagia, osteoporosis, liver cirrhosis, Crohn’s disease, hepatitis, alcoholism and bone fractures.
A meta-analysis conducted in 2006 indicated that postmenopausal women or women with other risk factors of osteoporosis who took averagely 45 mg of vitamin K (menachinon), had a considerably smaller number of osteoporotic fractures.
The need for vitamin K is acute for newborns and infants whose mothers have used anticonvulsants during pregnancy.
Figure 1. Vitamin K1: phyllochinon
Vitamin K content in food
Quantities of food products which should be consumed daily to obtain the recommended daily amount of vitamin K.
|11-22||23-50||50+||Pregnant women||Nursing women|
|Peas||54 g||143 g||214 g||268 g||250 g||357 g||357 g|
|Sauerkraut||24 g||65 g||97 g||121 g||113 g||161 g||161 g|
|Cauliflower||75 g||200 g||300 g||375 g||350 g||500 g||500 g|
|Broccoli||14 g||36 g||55 g||68 g||64 g||91 g||91 g|
|Barley malt||750 g||2000 g||3000 g||3750 g||3500 g||5000 g||5000 g|
|Peas||214 g||268 g||250 g|
|Sauerkraut||97 g||121 g||113 g|
|Cauliflower||300 g||375 g||350 g|
|Broccoli||55 g||68 g||64 g|
|Barley malt||3000 g||3750 g||3500 g|