Vitamin K: benefits, dosage, contraindications
Other name(s)
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Scientific name(s)
Phytonadione (K1), Menaquinone (K2), Menadione (K3)
Family or group:
Vitamins
Indications
Rating methodology
EFSA approval.
Hemorrhagic disease ✪✪✪✪✪
Vitamin K1 (phytonadione) administered orally or intramuscularly can prevent the classic hemorrhagic disease of the newborn. The risk of vitamin K deficiency is higher in newborns due to limited intestinal synthesis and low vitamin K content in breast milk. Thus, there may be deficiencies in newborns accompanied by a lack of coagulation factor synthesis with a significant hemorrhagic risk, which is why it is common to supplement all newborns with 0.5 to 1 mg of vitamin K1. A single intramuscular administration of vitamin K1 at a dose of 1 mg is considered the most effective method. The effects of vitamin K on late hemorrhagic disease of the newborn are unclear.
Posologie
Oral route
1 - 1 mg
1 - days
newborn
Bone Health ✪✪✪✪✪
Over the past decade, it has become evident that vitamin K plays an important role in human health beyond its well-established function in blood clotting. There is a range of consistent evidence in epidemiological and human intervention studies that clearly demonstrate vitamin K can improve bone health. Indeed, several interventional studies have reported rather mixed effects of supplementation with phylloquinone or short-chain menaquinones on bone status, most often showing a reduction in fracture risk when combined with increased calcium and vitamin D3 intake, as well as an increase in bone mineral density in osteoporotic individuals. In 2012, European health authorities (EFSA, the European Food Safety Authority, and the European Commission) determined that products containing vitamin K can claim to contribute to blood clotting and normal bone functioning.
Posologie
Oral route
70 µg
Adults
Osteoporosis ✪✪✪✪✪
Several clinical trials conducted among Japanese women have shown that the MK-4 form of vitamin K2, taken at a dose of 45 mg per day, improves BMD (bone mineral density) and reduces fracture risk among women with osteoporosis. Moreover, analyses of these studies' results and other similar studies show that vitamin K2, mainly used in the form of MK-4, can improve bone mineral density and reduce fracture risk by up to 80% among women with osteoporosis. In Japan, vitamin K is prescribed for osteoporosis prevention.
Posologie
Oral route
45 mg
4 - years
A longitudinal study of the effect of vitamin K2 on bone mineral density in postmenopausal women a comparative study with vitamin D3 and estrogen-progestin therapy.
Does vitamin K2 play a role in the prevention and treatment of osteoporosis for postmenopausal women: a meta-analysis of randomized controlled trials.
DIETARY SUPPLEMENT: VITAMIN K
Vitamin K to prevent fractures in older women: systematic review and economic evaluation
Short-term effect of vitamin K administration on prednisolone-induced loss of bone mineral density in patients with chronic glomerulonephritis.
Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trials.
Lung Cancer ✪✪✪✪✪
The reduction in mortality risk and increased survival duration appear quite significant among patients with lung cancer. Furthermore, relapse rates of hepatocellular carcinoma seem to be significantly lower than those with placebo.
Posologie
Oral route
42 - 46 mg
The effect of menatetrenone, a vitamin K2 analog, on disease recurrence and survival in patients with hepatocellular carcinoma after curative treatment: a pilot study.
Effect of menatetrenone, a vitamin k2 analog, on recurrence of hepatocellular carcinoma after surgical resection: a prospective randomized controlled trial.
Coronary Diseases ✪✪✪✪✪
The fact that arterial calcifications, particularly aortic and coronary, are a marker of cardiovascular risk raises the hypothesis of an effect at this level. A meta-analysis of 21 studies shows that a higher dietary intake of vitamin K1 (phylloquinone) or vitamin K2 (menaquinone) is associated with a reduced risk of coronary heart disease. On the other hand, supplementation with multivitamins enriched with vitamin K1 (500 mcg per day) over 3 years appears to reduce coronary artery calcification in older men and women, and reduce by 6% the progression of coronary artery calcification in patients with pre-existing coronary artery calcification, compared to supplementation with multivitamins alone.
Posologie
Oral
500 µg
3 - years
Adults
Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study
Association of vitamin K with cardiovascular events and all-cause mortality: a systematic review and meta-analysis
Properties
Hematological Effect
Blood coagulation is produced by a complex system of proteins working to prevent bleeding and form the blood clot. This system involves coagulation factors that depend on vitamin K: factor II (or prothrombin), factor VII, factor IX, factor X, and anticoagulation inhibitors: protein C, protein S, protein Z. All these molecules are synthesized by the liver except for protein S, which is also synthesized by endothelial cells.
Usages associés
Bone Density
Vitamins K play a crucial role in the biological activation of specific proteins, known as "gla proteins." This activation, accomplished through a process called gamma-carboxylation, allows these proteins to bind to calcium and exert their action. Among them, osteocalcin, produced exclusively in bone, plays a direct role in bone tissue calcification thanks to its ability to bind to hydroxyapatite, a major component of bone. Furthermore, vitamin K acts on osteoblasts, essential cells for bone formation and mineralization, by stimulating their production as well as that of stromal cells, contributing to bone growth. It also has a protective action by antagonizing certain effects of vitamin D on osteoclasts, the cells responsible for bone tissue degradation, thus helping maintain a balance between bone building and resorption. Moreover, vitamin K can reduce bone resorption by decreasing prostaglandin E2 production by osteoclasts, thus affecting calcium balance and interleukin 6 secretion in the bone. In summary, vitamin K is essential for maintaining bone health by regulating both their construction and degradation.
Usages associés
Anticancer
Vitamin K has been shown to inhibit cancer cell growth in vitro. Some vitamin K-dependent proteins are believed to act (once carboxylated) on receptors that interact with cell survival. Vitamin K is essential for the biological activity of a protein called Gas6 (growth arrest-specific gene 6 protein) involved in cell growth and apoptosis regulation, which may play an antiproliferative role and convey anticancer properties.
Usages associés
Hormonal Metabolism
Osteocalcin, a vitamin K-dependent protein, seems to play a role in improving insulin sensitivity. This insulin sensitivity can be regulated either by enhancing adiponectin activity in the body (a molecule produced by adipose tissue involved in lipid and glucose metabolism regulation) or by promoting the proliferation of pancreatic beta cells.
Cardiovascular
Vitamin K is a cofactor for the activation of "gla" proteins by carboxylation. Gla proteins are a group of proteins that have undergone a specific post-translational modification called gamma-carboxylation, performed by the enzyme gamma-glutamyl carboxylase in the presence of vitamin K. This modification gives gla proteins a strong affinity for calcium, allowing them to bind to calcium ions with great specificity and efficiency. Among these proteins is MGP (matrix carboxyglutamic acid protein), synthesized in cartilage and vascular walls, playing an inhibitory role in preventing tissue calcification. Vitamin K2 is also thought to restore the mitochondrial function of cardiac muscle, leading to increased adenosine triphosphate (ATP) production and improved muscle function.
Usages associés
Safety dosage
Adult from 18 year(s): 75 µg
Infant from 7 to 11 months: 10 µg
Child from 1 to 3 year(s): 12 µg
Child from 15 to 17 year(s): 65 µg
Child from 11 to 14 year(s): 45 µg
Child from 7 to 10 year(s): 30 µg
Child from 4 to 6 year(s): 20 µg
Interactions
Médicaments
Antidiabetics: moderate interaction
Research suggests that a high intake of vitamin K1 is associated with increased insulin sensitivity. Theoretically, a high intake of vitamin K1 may have additive effects with antidiabetic agents and increase the risk of hypoglycemia; dosage adjustments may be necessary.
Platelet aggregation inhibitors/Anticoagulants: strong interaction
Vitamin K counteracts the effects of oral anticoagulants such as warfarin. Excessive intake of vitamin K, from supplements or diet, can reduce the anticoagulant effect.
Antibiotics: moderate interaction
Vitamin K produced by intestinal bacteria is absorbed by the ileum. The destruction of vitamin K-producing bacteria by antibiotics may sometimes lead to vitamin K deficiency. It is suggested that antibiotics such as cefamandole (Mandol), which are excreted in large quantities in the bile, have a greater effect on vitamin K-producing bacteria. Moreover, some cephalosporins can interfere with vitamin K activity by directly inhibiting the production of coagulation factors in the liver. This interaction is more likely to occur with prolonged antibiotic therapy (10 days or more) in people with an insufficient dietary intake of vitamin K. Supplementation with vitamin K is not necessary for healthy individuals taking antibiotics for a short period.
Bile acid sequestrants: moderate interaction
By reducing dietary fat absorption, cholestyramine and colestipol may also reduce the absorption of fat-soluble vitamins such as vitamin K.
Orlistat: moderate interaction
Orlistat may reduce the absorption of some fat-soluble vitamins, although the extent of its effects on dietary vitamin K has not been determined. In healthy individuals, a slight decrease in plasma vitamin K levels may occur, but most often without any change in coagulation time. However, prolonged coagulation time may be seen if orlistat is combined with warfarin therapy.
Rifampicin: moderate interaction
Cases of vitamin K deficiency associated with Rifampicin treatment have been reported, leading to bleeding time prolongation. Suggested mechanisms are a reduction in intestinal absorption of vitamin K, destruction of vitamin K-producing intestinal bacteria, and enzymes that regenerate vitamin K from its inactive metabolite. Symptomatic vitamin K deficiency is more likely to occur in individuals with insufficient dietary intake or other associated factors.
Plantes ou autres actifs
Vitamin K: moderate interaction
Taking vitamin E at doses equal to or greater than 800 IU/day may decrease the effects of vitamin K.
Precautions
Pregnant woman from 18 year(s): use with caution
Vitamin K is safe if used orally in amounts not exceeding the recommended dietary allowance (RDA). The tolerable upper intake level for vitamin K during pregnancy and breastfeeding has not been set.
Breastfeeding woman from 18 year(s): use with caution
Vitamin K is safe if used orally in amounts not exceeding the recommended dietary allowance (RDA). The tolerable upper intake level for vitamin K during pregnancy and breastfeeding has not been set.
