Vitamin K: benefits, dosage, contraindications
Scientific name(s)
Phytonadione (K1), Menaquinone (K2), Menadione (K3)
Family or group:
Vitamins
Indications
Scoring methodology
EFSA approval.
Hemorrhagic disease ✪✪✪✪✪
Vitamin K1 (phytonadione) administered orally or intramuscularly can prevent classic hemorrhagic disease of the newborn. Indeed, the risk of vitamin K deficiency is greater in the newborn due to limited intestinal synthesis and the low vitamin K content of breast milk. Thus, deficiencies can occur in newborns accompanied by a defect in the synthesis of clotting factors with a significant risk of bleeding, which is why it is customary 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 not clear.
Posologie
Oral
1 - 1 mg
1 - days
newborn
Bone health ✪✪✪✪✪
Over the past decade, it has become clear that vitamin K has an important role to play in human health that goes beyond its well-established function in blood coagulation. There is a body of consistent evidence from epidemiological and human intervention studies that clearly demonstrates that vitamin K can improve bone health. Indeed, a number of 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 intake of calcium and vitamin D3, as well as an increase in bone mineral density in people with osteoporosis. In 2012, European health authorities (EFSA, European Food Safety Authority and the European Commission) concluded that products containing vitamin K may claim to contribute to blood coagulation and the normal functioning of bones.
Posologie
Oral administration
70 µg
Adults
Osteoporosis ✪✪✪✪✪
Several clinical trials conducted in Japanese women have shown that the MK-4 form of vitamin K2, taken at 45 mg per day, improves BMD (bone mineral density) and reduces the risk of fracture in women with osteoporosis. Furthermore, analyses of the results of these studies and other similar studies show that vitamin K2, primarily used in the form of MK-4, can improve bone mineral density and reduce the risk of fractures by up to 80% in women with osteoporosis. In Japan, vitamin K is prescribed for the prevention of osteoporosis.
Posologie
Orally
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 the risk of mortality and the extension of survival time appear to be quite significant in patients with lung cancer. In addition, recurrence rates of hepatocellular carcinoma appear to be markedly lower than those with placebo.
Posologie
Orally
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 heart disease ✪✪✪✪✪
The fact that arterial calcifications, particularly aortic and coronary calcifications, 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 (phytonadione) or vitamin K2 (menaquinone) is associated with a reduced risk of coronary heart disease. Furthermore, supplementation with multivitamins enriched with vitamin K1 (500 mcg per day) for 3 years appears to reduce coronary artery calcification in older men and women, and to reduce by 6% the progression of coronary artery calcification in patients with preexisting coronary artery calcification, compared with multivitamin supplementation alone.
Posologie
Oral administration
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
Hematologic effect
Blood coagulation is carried out by a complex system of proteins that work to prevent bleeding and form a blood clot. This system involves vitamin K–dependent clotting factors: factor II (prothrombin), factor VII, factor IX, factor X, and coagulation inhibitors: protein C, protein S, and protein Z. All of these molecules are synthesized by the liver, except for protein S, which is also produced by endothelial cells.
Usages associés
Bone density
Vitamin K plays a crucial role in the biological activation of specific proteins known as 'Gla-proteins'. This activation, carried out by a process called gamma-carboxylation, enables these proteins to bind calcium and exert their function. Among them, osteocalcin, produced exclusively in bone, plays a direct role in mineralizing bone tissue thanks to its ability to bind hydroxyapatite, a major component of bone. In addition, vitamin K acts on osteoblasts, the cells essential for bone formation and mineralization, by stimulating their production as well as that of stromal cells, which contributes to bone growth. It also has a protective effect by antagonizing certain effects of vitamin D on osteoclasts, the cells responsible for bone resorption, thereby helping to maintain a balance between bone formation and breakdown. Furthermore, vitamin K can reduce bone resorption by decreasing prostaglandin E2 production by osteoclasts, thus affecting calcium balance and interleukin-6 secretion in bone. In summary, vitamin K is essential for maintaining bone health by regulating both bone formation and degradation.
Usages associés
Anticancer
It has been shown that vitamin K inhibits the growth of cancer cells in vitro. It is thought that some vitamin K-dependent proteins can act (once carboxylated) on receptors that interact with cell survival. Indeed, vitamin K is essential for the biological activity of a protein called Gas6 (growth arrest-specific gene 6 protein) which is involved in the regulation of cell growth and apoptosis and may play an antiproliferative role and confer certain anticancer properties.
Usages associés
Hormone metabolism
Osteocalcin is a vitamin K-dependent protein that appears to play a role in improving insulin sensitivity. This insulin sensitivity may be regulated either by enhancing the activity of adiponectin in the body (a molecule produced by adipose tissue involved in the regulation of lipid and glucose metabolism), or by promoting the proliferation of pancreatic beta cells.
Cardiovascular
Vitamin K is a cofactor for the activation of "gla" proteins by carboxylation. The Gla proteins are a group of proteins that have undergone a specific post-translational modification called gamma-carboxylation, carried out by the enzyme gamma-glutamyl carboxylase in the presence of vitamin K. This modification gives Gla proteins a high affinity for calcium, allowing them to bind calcium ions with great specificity and efficiency. Among these proteins is MGP (matrix Gla protein), which is synthesized in cartilage and vascular walls and plays an inhibitory role in preventing tissue calcification. Vitamin K2 is also thought to restore mitochondrial function in cardiac muscle, resulting in increased production of adenosine triphosphate (ATP) and improved muscle function.
Usages associés
Safe dosage
Adults 18 years and older: 75 µg
Infants 7 to 11 months: 10 µg
Children 1 to 3 years: 12 µg
Children 15 to 17 years: 65 µg
Children 11 to 14 years: 45 µg
Child aged 7 to 10 years: 30 µg
Child aged 4 to 6 years: 20 µg
Interactions
Médicaments
Antidiabetic: moderate interaction
Research suggests that high consumption of vitamin K1 is associated with increased insulin sensitivity. Theoretically, a high intake of vitamin K1 may have additive effects with antidiabetic drugs and increase the risk of hypoglycemia; dose adjustments may be necessary.
Antiplatelet agents/Anticoagulant: strong interaction
Vitamin K neutralizes the effects of oral anticoagulants such as warfarin. Excessive vitamin K intake from supplements or food can reduce the anticoagulant effect.
Antibiotics: moderate interaction
Vitamin K produced by intestinal bacteria is absorbed in the ileum. Destruction of vitamin K-producing bacteria by antibiotics can sometimes lead to vitamin K deficiency. It has been suggested that antibiotics such as cefamandole (Mandol), which are excreted in large amounts in bile, have a greater effect on vitamin K-producing bacteria. In addition, some cephalosporins may interfere with vitamin K activity by directly inhibiting the production of clotting factors in the liver. This interaction is more likely to occur with prolonged antibiotic therapy (10 days or more) in people with inadequate dietary vitamin K intake. Vitamin K supplementation is not necessary for healthy people taking antibiotics for a short duration.
Bile acid sequestrants: moderate interaction
By reducing the absorption of dietary fats, cholestyramine and colestipol can also reduce the absorption of fat-soluble vitamins such as vitamin K.
Orlistat: moderate interaction
Orlistat may reduce the absorption of certain fat-soluble vitamins, although the extent of its effects on dietary vitamin K has not been determined. In healthy people, a slight decrease in plasma vitamin K levels may occur, but most often without any change in clotting time. However, prolonged clotting time may be seen if Orlistat is combined with warfarin therapy.
Rifampin: moderate interaction
Cases of vitamin K deficiency associated with rifampin treatment have been reported, resulting in prolonged bleeding time. Suggested mechanisms include reduced intestinal absorption of vitamin K, destruction of intestinal bacteria that produce vitamin K, and destruction of enzymes that regenerate vitamin K from its inactive metabolite. Symptomatic vitamin K deficiency is more likely to occur in people with inadequate dietary intake or other associated factors.
Plantes ou autres actifs
Vitamin K: moderate interaction
Taking vitamin E at doses greater than or equal to 800 IU/day may reduce the effects of vitamin K.
Precautions
Pregnant woman aged 18 years and over: 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 established. nn
Breastfeeding woman aged 18 years and over: 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 established. nn
