Vitamin ok performs a key position in serving to the blood clot, stopping extreme bleeding. Not like many different nutritional vitamins, vitamin ok just isn’t sometimes used as a dietary complement. A very powerful of those compounds seems to be vitamin k1 and vitamin k2.
Vitamin k2 is a bunch of compounds largely obtained from meats, cheeses, and eggs, and synthesized by micro organism. Not too long ago, some folks have seemed to vitamin k2 to deal with osteoporosis and steroid-induced bone loss, however the analysis is conflicting. At this level there’s not sufficient information to suggest utilizing vitamin k2 for osteoporosis.
Why Do Individuals Take Vitamin K?
Vitamin ok performs a key position in serving to the blood clot, stopping extreme bleeding. Not like many different nutritional vitamins, vitamin ok just isn’t sometimes used as a dietary complement. Vitamin ok is definitely a bunch of compounds.
Not too long ago, some folks have seemed to vitamin k2 to deal with osteoporosis and steroid-induced bone loss, however the analysis is conflicting. At this level there’s not sufficient information to suggest utilizing vitamin k2 for osteoporosis.
Função[Editar | Editar Código-Fonte]
A vitamina ok, ou vitamina anti-hemorrágica, denota um grupo de compostos lipofílicos derivados do isopreno.
Em 1929, henrik dam verificou o desenvolvimento de hemorragia subcutânea e anemia em galinhas submetidas à alimentação livre de lipídios. Posteriormente, constatou-se que a condição destes animais poderia ser revertida pela oferta de extratos de fígado e vários tecidos de plantas, nos quais identificou-se uma substância anti-hemorrágica solúvel presente em lipídeos. As menaquinonas naturais variam de mk-4 a mk-13.
O papel mais conhecido da vitamina ok está relacionado com a sua ação no processo de coagulação sanguínea. A hidroquinona, forma reduzida e ativa da vitamina, atua como cofator para uma enzima carboxilase, responsável pela reação de carboxilação de resíduos de ácido glutâmico (glu) presentes em proteínas dependentes de vitamina ok. a carboxilação do glu, por sua vez, leva à formação do ácido γ-carboxiglutâmico (gla), tornando as proteínas biologicamente ativas. Uma parte importante do metabolismo de vitamina ok está relacionada a sua through de recuperação, denominada de ciclo da vitamina ok. quando um resíduo de glutamato é carboxilado, a vitamina ok sofre oxidação, gerando 2,3-epoxi vitamina ok. esse metabólito é convertido novamente à sua forma ativa, pela ação da enzima microssomal, epoxi redutase de vitamina ok e uma ou mais quinona redutases de vitamina ok. alguns anticoagulantes, como a warfarina e o dicumarol atuam bloqueando a redução do epóxido de vitamina ok, impedindo o processo de reutilização da vitamina.
Portanto, a vitamina é importante no desenvolvimento precoce do esqueleto e na manutenção do osso maduro sadio. Absorção, transporte e metabolismo [ editar | editar código-fonte ]
a vitamina ok fornecida pela alimentação é absorvida predominantemente na borda em escova do íleo e integrada aos quilomicrons circulantes para exocitose no sistema linfático. As filoquinona e menaquinona (especialmente a mk7) são incorporadas em micelas mistas contendo sais biliares e outros lipídios dietéticos.
Os quilomicrons são secretados de dentro das microvilosidades para os capilares linfáticos, que alcançam a corrente sanguínea through ducto torácico. Foi constatada a presença de mk-4 em maior quantidade que as filoquinonas, no cérebro, rins e pâncreas e quantidades inferiores, no coração e pulmão. Em quantidades fisiológicas, a concentração plasmática pós-prandial de filoquinona atinge pico em 6 horas, retornando à linha de base em 24 horas, enquanto que as menaquinonas de cadeia longa permanecem na circulação por até 72 horas [4].
Contudo, a presença de gorduras na dieta possibilita um aumento na absorção (podendo conter de 30 a 60 µg de dihidrofiloquinonas em 100g de alimento), possivelmente pelo estímulo da secreção biliar e da formação de micelas [6]. Neste sentido, foi verificado que a biodisponibilidade de 1 mg de filoquinona, no espinafre, em seres humanos foi menor (4 %) quando comparada à absorção do alimento adicionado com manteiga (13 %). A importância da menaquinona obtida pela microflora intestinal foi evidenciada, a partir de observações clínicas de pacientes que ingeriam quantidade nulas de vitamina ok e que só desenvolviam sangramentos severos com a administração de altas doses de antibióticos.
No entanto, ainda não foi confirmada a ocorrência absorção direta da vitamina no cólon [12]. Através da utilização de cromatografia líquida de alta eficiência (clae), muitos estudos identificaram quantidades relevantes de filoquinona em vegetais verdes folhosos e óleos vegetais (tabela 1)[4,9-10]. Também são encontradas baixas quantidades de menaquinonas em outros órgãos como rins, coração e músculo [4,9].
Em adultos, a hipovitaminose de vitamina ok não é comum, pois está amplamente distribuída nos alimentos de origem vegetal. A deficiência clínica da vitamina tem sido classicamente descrita como hipoprotrombinemia e está associada ao aumento no tempo de protrombina. Em casos graves, pode haver quadros hemorrágicos ameaçadores à vida como um resultado de uma atividade inadequada dos fatores dependentes de vitamina ok. a falta da vitamina, promove a secreção de protrombina sub-carboxilada no plasma, chamada proteína induzida pela ausência de vitamina ok [5,10].
Para a profilaxia da doença hemorrágica do recém-nascido é preconizado a dose de 1 mg de vitamina ok intramuscular ao nascimento. Uma outra forma importante da deficiência de vitamina ok está relacionada a superdosagens de vitamina a e vitamina e como fatores antinutricionais específicos. Com relação a vitamina a a hipoprotrombinemia pode ser revertida, através do aumento da administração de vitamina ok. no caso da vitamina e existem referências a potencialização da atividade de anticoagulantes, como a varfarina [6].
Em termos quantitativos, a pesquisa demonstrou que, para cada 100μg de vitamina k1 ingeridos por dia, diminuíam-se em 17% as possibilities de desenvolver o diabetes.
Contents
For vitamin ok, the shape mostly used as a dietary complement or in a multi-vitamin, see phytomenadione
vitamin ok refers to structurally related, fat-soluble vitamers present in meals and marketed as dietary dietary supplements. [2] the whole synthesis entails last modification of those so-called “gla proteins” by the enzyme gamma-glutamyl carboxylase that makes use of vitamin ok as a cofactor.
[3] the presence of uncarboxylated proteins signifies a vitamin ok deficiency. Analysis means that deficiency of vitamin ok can also weaken bones, doubtlessly contributing to osteoporosis, and will promote calcification of arteries and different tender tissues. Vitamin ok contains two pure vitamers: vitamin ok 1 (phylloquinone) and vitamin ok 2 (menaquinone).
[4] vitamin ok 2 , in flip, consists of quite a lot of associated chemical subtypes, with differing lengths of carbon aspect chains fabricated from isoprenoid teams of atoms. The 2 most studied ones are menaquinone-4 (mk-4) and menaquinone-7 (mk-7). Vitamin ok 1 is made by crops, and is present in highest quantities in inexperienced leafy greens, as a result of it’s instantly concerned in photosynthesis.
Animals can also convert it to vitamin ok 2 , variant mk-4. Micro organism within the intestine flora may also convert ok 1 into mk-4. All types of ok 2 apart from mk-4 can solely be produced by micro organism, which use these throughout anaerobic respiration.
Vitamin ok 3 (menadione), an artificial type of vitamin ok, was used to deal with vitamin ok deficiency, however as a result of it interferes with the operate of glutathione, it’s not used this manner in human diet. [2]
definition [ edit ]
vitamin ok refers to structurally related, fat-soluble vitamers present in meals and marketed as dietary dietary supplements. “vitamin k” embody a number of chemical compounds.
These are related in construction in that they share a quinone ring, however differ within the size and diploma of saturation of the carbon tail and the variety of repeating isoprene items within the aspect chain (see figures in chemistry part). Plant-sourced varieties are primarily vitamin ok 1 . Animal-sourced meals are primarily vitamin ok 2 .
[1][6][7] vitamin ok has a number of roles: a vital nutrient absorbed from meals, a product synthesized and marketed as a part of a multi-vitamin or as a single-vitamin dietary complement, and a prescription remedy for particular functions. The present ais for grownup men and women ages 19 and older are 90 and 120 μg/day, respectively, for being pregnant is 90 μg/day, and for lactation is 90 μg/day. As for security, the academy units tolerable higher consumption ranges (often called “upper limits”) for nutritional vitamins and minerals when proof is adequate.
[5]
within the european union, enough consumption is outlined the identical method as within the us. For men and women over age 18 the enough consumption is about at 70 μg/day, for being pregnant 70 μg/day, and for lactation 70 μg/day. [15] the world well being group doesn’t have suggestions on vitamin ok fortification.
Vitamin ok 2 is primarily from animal-sourced meals, with poultry and eggs a lot better sources than beef, pork or fish. [4] an exception could also be infants who’re at an elevated danger of deficiency whatever the vitamin standing of the mom throughout being pregnant and breast feeding because of poor switch of the vitamin to the placenta and low quantities of the vitamin in breast milk. [18]
secondary deficiencies can happen in individuals who devour enough quantities, however have malabsorption situations, akin to cystic fibrosis or power pancreatitis, and in individuals who have liver injury or illness.
[2] secondary vitamin ok deficiency may also happen in individuals who have a prescription for a vitamin ok antagonist drug, akin to warfarin. [18] late onset prevalence reported at 35 instances per 100,000 stay births in infants who had not acquired prophylaxis at or shortly after beginning. [23] vitamin ok deficiency bleeding happens extra ceaselessly within the asian inhabitants in comparison with the caucasian inhabitants.
[18]
managing warfarin remedy [ edit ]
warfarin is an anticoagulant drug. It features by inhibiting an enzyme that’s answerable for recycling vitamin ok to a useful state. As a consequence, proteins that must be modified by vitamin ok aren’t, together with proteins important to blood clotting, and are thus not useful.
[25] some meals are so excessive in vitamin ok 1 that medical recommendation is to keep away from these (examples: collard greens, spinach, turnip greens) totally, and for meals with a modestly excessive vitamin content material, maintain consumption as constant as attainable, in order that the mix of vitamin consumption and warfarin maintain the anti-clotting exercise within the therapeutic vary. [26]
vitamin ok is a therapy for bleeding occasions brought on by overdose of the drug. [27] oral vitamin ok is utilized in conditions when an individual’s worldwide normalised ratio is bigger than 10 however there is no such thing as a lively bleeding.
[30] for people, and for animals which have consumed both the rodenticide or rats poisoned by the rodenticide, therapy is extended administration of enormous quantities of vitamin ok.[31][32] this dosing should typically be continued for as much as 9 months in instances of poisoning by “superwarfarin” rodenticides akin to brodifacoum. Oral vitamin ok 1 is most well-liked over different vitamin ok 1 routes of administration as a result of it has fewer uncomfortable side effects. [33]
strategies of evaluation [ edit ]
a rise in prothrombin time, a coagulation assay, has been used as an indicator of vitamin ok standing, but it surely lacks adequate sensitivity and specificity for this software.
If uncarboxylated prothrombin is being measured, this “protein induced by vitamin k absence/antagonism (pivka-ii)” is elevated in vitamin ok deficiency. The take a look at is used to evaluate danger of vitamin ok–poor bleeding in new child infants. The ratio of uncarboxylated osteocalcin to carboxylated osteocalcin will increase with vitamin ok deficiency.
[35] matrix gla protein should bear vitamin ok dependent phosphorylation and carboxylation. [36]
uncomfortable side effects [ edit ]
no recognized toxicity is related to excessive oral doses of the vitamin ok 1 or (vitamin ok 2 ) types of vitamin ok, so regulatory companies from us, japan and european union concur that no tolerable higher consumption ranges must be set. [5][9][10] nevertheless, vitamin ok 1 has been related to extreme opposed reactions akin to bronchospasm and cardiac arrest when given intravenously.
The response is described as a nonimmune-mediated anaphylactoid response, with incidence of three per 10,000 remedies. The vast majority of reactions occurred when polyoxyethylated castor oil was used because the solubilizing agent. Menadione, an artificial compound typically known as vitamin ok 3 , is used within the pet meals business as a result of as soon as consumed it’s transformed to vitamin ok 2 .
[2] analysis with ok 5 suggests it could inhibit fungal progress in fruit juices. In menaquinone, the aspect chain consists of a various variety of vitamin ok(menaquinone). The construction of phylloquinone, vitamin ok 1 , is marked by the presence of a phytyl sidechain.
[40] vitamin ok 1 seems as a yellow viscous liquid at rom temperature because of its absorption of violet gentle within the uv-vis spectra. Mk-4 is the commonest type. [42]
a pattern of phytomenadione for injection, additionally known as phylloquinone
conversion of vitamin ok 1 to vitamin ok 2 [ edit ]
in animals, the mk-4 type of vitamin ok 2 is produced by conversion of vitamin ok 1 within the testes, pancreas, and arterial partitions.
[21] whereas main questions nonetheless encompass the biochemical pathway for this transformation, the conversion just isn’t depending on intestine micro organism, because it happens in germ-free rats[43] and in parenterally administered ok 1 in rats. [44][45] there’s proof that the conversion proceeds by removing of the phytyl tail of ok 1 to provide menadione (additionally known as vitamin ok 3 ) as an intermediate, which is then prenylated to provide mk-4. [46]
physiology [ edit ]
in animals, vitamin ok is concerned within the carboxylation of sure glutamate residues in proteins to type gamma-carboxyglutamate (gla) residues.
The modified residues are sometimes (however not at all times) located inside particular protein domains known as gla domains. The method requires bile and pancreatic juices. Estimates for absorption are on the order of 80% for vitamin ok 1 in its free type (as a dietary complement) however a lot decrease when current in meals.
For instance, the absorption of vitamin ok from kale and spinach – meals recognized as having a excessive vitamin ok content material – are on the order of 4% to 17% no matter whether or not uncooked or cooked. [4] much less info is obtainable for absorption of vitamin ok 2 from meals. Animal research present that it additionally components into absorption of nutritional vitamins e and ok 1 .
[55] the identical examine predicts potential interplay between sr-bi and cd36 proteins as properly. [55] the drug ezetimibe inhibits npc1l1 inflicting a discount in ldl cholesterol absorption in people, and in animal research, additionally reduces vitamin e and vitamin ok 1 absorption. An anticipated consequence could be that administration of ezetimibe to individuals who take warfarin (a vitamin ok antagonist) would potentiate the warfarin impact.
This has been confirmed in people. [55]
biochemistry [ edit ]
operate in animals [ edit ]
cyclic mechanism of motion of vitamin ok
vitamin ok hydroquinone vitamin ok epoxide in each instances r represents the isoprenoid aspect chain
vitamin ok is distributed in another way inside animals relying on its particular homologue. Vitamin ok 1 is principally current within the liver, coronary heart and pancreas, whereas mk-4 is healthier represented within the kidneys, mind and pancreas.
The liver additionally incorporates longer chain homologues mk-7 to mk-13. This can be a considerably unusual posttranslational modification of the protein, which is then often called a “gla protein”. The binding of calcium ions on this method fairly often triggers the operate or binding of gla-protein enzymes, such because the so-called vitamin ok–dependent clotting components mentioned beneath.
[58] one other enzyme then oxidizes vitamin ok hydroquinone to permit carboxylation of glu to gla; this enzyme is known as gamma-glutamyl carboxylase[59] or the vitamin ok–dependent carboxylase. The carboxylation response solely proceeds if the carboxylase enzyme is ready to oxidize vitamin ok hydroquinone to vitamin ok epoxide on the similar time. The discount and subsequent reoxidation of vitamin ok coupled with carboxylation of glu is known as the vitamin ok cycle.
[60] people are hardly ever poor in vitamin ok as a result of, partly, vitamin ok 2 is repeatedly recycled in cells. [24] this ends in decreased concentrations of vitamin ok and vitamin ok hydroquinone in tissues, such that the carboxylation response catalyzed by the glutamyl carboxylase is inefficient. The bone gla protein osteocalcin, the calcification-inhibiting matrix gla protein (mgp), the cell progress regulating progress arrest particular gene 6 protein, and the 4 transmembrane gla proteins, the operate of which is at current unknown.
The gla area is answerable for high-affinity binding of calcium ions (ca2+) to gla proteins, which is commonly vital for his or her conformation, and at all times vital for his or her operate. [57]
gla proteins are recognized to happen in all kinds of vertebrates: mammals, birds, reptiles, and fish. The venom of quite a lot of australian snakes acts by activating the human blood-clotting system.
[7][65]
operate in micro organism [ edit ]
many micro organism, together with escherichia coli discovered within the giant gut, can synthesize vitamin ok 2 (mk-7 as much as mk-11),[66] however not vitamin ok 1 . Inexperienced algae and a few species of cyanobacteria (typically known as blue-green algae) are capable of synthesize vitamin ok 1 . [65] within the vitamin ok 2 synthesizing micro organism, menaquinone transfers two electrons between two totally different small molecules, throughout oxygen-independent metabolic power manufacturing processes (anaerobic respiration).
[67] for instance, a small molecule with an extra of electrons (additionally known as an electron donor) akin to lactate, formate, or nadh, with the assistance of an enzyme, passes two electrons to menaquinone. Including two electrons to fumarate or nitrate converts the molecule to succinate or nitrite plus water, respectively. [67] a few of these reactions generate a mobile power supply, atp, in a fashion just like eukaryotic cell cardio respiration, besides the ultimate electron acceptor just isn’t molecular oxygen, however fumarate or nitrate.
In cardio respiration, the ultimate oxidant is molecular oxygen, which accepts 4 electrons from an electron donor akin to nadh to be transformed to water. E. coli, as facultative anaerobes, can perform each cardio respiration and menaquinone-mediated anaerobic respiration. [67]
historical past [ edit ]
in 1929, danish scientist henrik dam investigated the position of ldl cholesterol by feeding chickens a cholesterol-depleted weight loss program.
[68] he initially replicated experiments reported by scientists on the ontario agricultural school. [70] dam discovered that these defects couldn’t be restored by including purified ldl cholesterol to the weight loss program. It appeared that – along with the ldl cholesterol – a second compound had been extracted from the meals, and this compound was known as the coagulation vitamin.
The brand new vitamin acquired the letter ok as a result of the preliminary discoveries have been reported in a german journal, during which it was designated as koagulationsvitamin. Edward adelbert doisy of saint louis college did a lot of the analysis that led to the invention of the construction and chemical nature of vitamin ok.[71] dam and doisy shared the 1943 nobel prize for medication for his or her work on vitamin ok 1 and ok 2 revealed in 1939. [72]
for a number of many years, the vitamin ok–poor chick mannequin was the one technique of quantifying vitamin ok in varied meals: the chicks have been made vitamin ok–poor and subsequently fed with recognized quantities of vitamin ok–containing meals.
The extent to which blood coagulation was restored by the weight loss program was taken as a measure for its vitamin ok content material. Three teams of physicians independently discovered this: biochemical institute, college of copenhagen (dam and johannes glavind), college of iowa division of pathology (emory warner, kenneth brinkhous, and harry pratt smith), and the mayo clinic (hugh butt, albert snell, and arnold osterberg). [79] there’s a subset of literature on supplementation with vitamin ok 2 mk-4 and bone well being.
In animal research, animals that lack the gene for mgp exhibit calcification of arteries and different tender tissues. [4] in people, keutel syndrome is a uncommon recessive genetic dysfunction related to abnormalities within the gene coding for mgp and characterised by irregular diffuse cartilage calcification. [80] these observations led to a idea that in people, inadequately carboxylated mgp, because of low dietary consumption of the vitamin, may lead to elevated danger of arterial calcification and coronary coronary heart illness.
[4]
in meta-analyses of inhabitants research, low consumption of vitamin ok was related to inactive mgp, arterial calcification[81] and arterial stiffness. [82][83] decrease dietary intakes of vitamin ok 1 and vitamin ok 2 have been additionally related to larger coronary coronary heart illness. [36][84] when blood focus of circulating vitamin ok 1 was assessed there was an elevated danger in all trigger mortality linked to low focus.
[85][86] in distinction to those inhabitants research, a assessment of randomized trials utilizing supplementation with both vitamin ok 1 or vitamin ok 2 reported no position in mitigating vascular calcification or decreasing arterial stiffness. [87]
different [ edit ]
inhabitants research recommend that vitamin ok standing could have roles in irritation, mind operate, endocrine operate and an anti-cancer impact. For all of those, there’s not adequate proof from intervention trials to attract any conclusions.
[4] from a assessment of observational trials, long-term use of vitamin ok antagonists as anticoagulation remedy is related to decrease most cancers incidence on the whole. [89][90]
references [ edit ]
additional studying [ edit.
Explore:
The main type is called phylloquinone, found in green leafy vegetables like collard greens, kale, and spinach.
Menaquinones can also be produced by bacteria in the human body. [1]
vitamin ok helps to make varied proteins which might be wanted for blood clotting and the constructing of bones. Due to this, it hardly ever reaches poisonous ranges within the physique even with excessive intakes, as could typically happen with different fat-soluble nutritional vitamins.
Vitamin ok and well being
blood clots vitamin ok helps to make 4 of the 13 proteins wanted for blood clotting, which stops wounds from repeatedly bleeding to allow them to heal. People who find themselves prescribed anticoagulants (additionally known as blood thinners) to stop blood clots from forming within the coronary heart, lung, or legs are sometimes knowledgeable about vitamin ok. due to its blood clotting motion, vitamin ok has the potential to counteract the consequences of blood thinning medicines. Bone well being vitamin ok is concerned with the manufacturing of proteins in bone, together with osteocalcin, which is required to stop the weakening of bones.
Some research have proven that larger vitamin ok intakes are related to a decrease incidence of hip fractures and low bone density. As well as, low blood ranges of vitamin ok have been linked with low bone density. [2] a report from the nurses’ well being examine suggests that ladies who get no less than 110 mcg of vitamin ok a day are 30% much less prone to break a hip than ladies who get lower than that.
[3] among the many nurses, consuming a serving of lettuce or different inexperienced, leafy vegetable a day lower the danger of hip fracture in half in comparison with consuming one serving every week. [4, 5] nevertheless, the outcomes of scientific trials and meta-analyses have been conflicting whether or not vitamin ok dietary supplements scale back bone fractures. [1] this can be because of quite a lot of different components that have an effect on bone well being, together with a scarcity of calcium, vitamin d, and weight-bearing train, all of which could masks a good thing about vitamin ok supplementation.
Coronary heart illness just a few research have researched the position of vitamin ok for coronary heart well being. As a result of analysis on this space could be very restricted, further research are wanted earlier than a certain quantity of vitamin ok past the usual suggestion is proposed for this situation. The restricted quantity of blood clotting proteins at beginning will increase the danger of bleeding in infants if they aren’t given vitamin ok dietary supplements.
The next are the commonest indicators of a deficiency. An extended time for blood to clot or a protracted prothrombin time (as measured in a doctor’s workplace)
bleeding
hemorrhaging
osteopenia or osteoporosis
do you know?
So, drizzle some olive oil or add diced avocado to your favourite leafy inexperienced salad!. Feskanich d, weber p, willett wc, rockett h, sales space sl, colditz ga. vitamin ok consumption and hip fractures in ladies: a potential examine. Sales space sl, tucker kl, chen h, et al.
Dietary vitamin ok intakes are related to hip fracture however not with bone mineral density in aged women and men. Vitamin ok consumption and bone mineral density in men and women. Phrases of use
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