Vitamin K, also known as vitamin K1, vitamin K2 and vitamin K3, is a group fat-soluble vitamins that are needed for the synthesis of the proteins that help control bleeding (clotting factors) and thus for the normal clotting of blood. If you don't have enough vitamin K, you may bleed too much. Vitamin K also helps your body by making proteins needed for healthy bones and other tissues. Vitamin K is a vitamin found in leafy green vegetables, broccoli, and Brussels sprouts.
Vitamin K was identified in 1929 by Danish scientist Henrik Dam when he investigated the role of cholesterol by feeding chickens a cholesterol-depleted diet. After several weeks, the animals developed hemorrhages and started bleeding. These defects could not be restored by adding purified cholesterol to the diet. It appeared that—together with the cholesterol—a second compound had been extracted from the food, and this compound was called the coagulation vitamin. The new vitamin received the letter K because the initial discoveries were reported in a German journal, in which it was designated as Koagulationsvitamin.
Unlike water-soluble vitamins (B-complex and C) that need regular replacement in the body, fat-soluble vitamins (A, D, E and K) are stored in the liver and fatty tissues, and are eliminated much more slowly than water-soluble vitamins.
Vitamin K comes in three forms: phylloquinone, menaquinone, and menadione. Phylloquinone, or vitamin K1, is found in green leafy vegetables, and helps bones absorb and store calcium. One recent study showed that increased amounts of vitamin K in the diet might lower the risk of hip fracture; over time, a shortage of vitamin K could lead to osteoporosis. Menaquinone, or vitamin K2, is manufactured in the body by naturally occurring intestinal bacteria. People that regularly take antibiotics or have a medical condition that upsets the balance of bacteria in the intestine are at risk of developing a vitamin K deficiency. Menadione, or vitamin vitamin K3, is an artificial form of vitamin K, which is water-soluble and more easily absorbed by people who have problems with fat absorption.
In the body, vitamin K plays a major role in blood clotting. So it is used to reverse the effects of "blood thinning" medications when too much is given; to prevent clotting problems in newborns who don't have enough vitamin K; and to treat bleeding caused by medications including salicylates, sulfonamides, quinine, quinidine, or antibiotics. Vitamin K is also given to treat and prevent vitamin K deficiency, a condition in which the body doesn't have enough vitamin K. It is also used to prevent and treat weak bones (osteoporosis) and relieve itching that often accompanies a liver disease called biliary cirrhosis.
People apply vitamin K to the skin to remove spider veins, bruises, scars, stretch marks, and burns. It is also used topically to treat rosacea, a skin condition that causes redness and pimples on the face. After surgery, vitamin K is used to speed up skin healing and reduce bruising and swelling.
Healthcare providers also give vitamin K by injection to treat clotting problems.
An increased understanding of the role of vitamin K in the body beyond blood clotting led some researchers to suggest that the recommended amounts for dietary intake of vitamin K be increased. In 2001, the National Institute of Medicine Food and Nutrition Board increased their recommended amounts of vitamin K slightly, but refused to make larger increases. They explained there wasn't enough scientific evidence to make larger increases in the recommended amount of vitamin K.
It is rare to have a vitamin K deficiency. That's because in addition to being found in leafy green foods, the bacteria in your intestines can make vitamin K. Sometimes taking antibiotics can kill the bacteria and lead to a mild deficiency, mostly in people with low levels to begin with.
Persons deficient in vitamin K are first and foremost likely to have symptoms related to problematic blood clotting or bleeding. These symptoms can include heavy menstrual bleeding, gum bleeding, bleeding within the digestive tract, nose bleeding, easy bruising, blood in the urine, prolonged clotting times, hemorrhaging, and anemia. A second set of vitamin K deficiency-related symptoms involves bone problems. These symptoms can include loss of bone (osteopenia), decrease in bone mineral density (osteoporosis), and fractures -- including common age-related fractures like that of the hips. Yet another set of vitamin K deficiency-related symptoms involves excess deposition of calcium in soft tissues. These calcification-based problems include hardening of the arteries or calcium-related problems with heart valve function.
Other things that may lead to vitamin K deficiency include:
Health problems that can prevent your body from absorbing vitamin K, such as gallbladder or biliary disease, cystic fibrosis, celiac disease, and Crohn's disease
Liver disease
Taking blood-thinners, such as warfarin (Coumadin)
Long-term hemodialysis
Serious burns
The signs and symptoms associated with vitamin K deficiency may include:
excessive bleeding, including:
heavy menstrual bleeding
gum bleeding
nosebleeding
bleeding within the digestive tract
bleeding from the gastrointestinal (GI) tract
blood in the urine and/or stool
excessive bleeding from wounds, punctures, and injection or surgical sites
an increased prothrombin time (PT/INR)
easy bruising
problems with calcification of the blood vessels or heart valves
problems with bone fracture or bone weakening
In hemorrhagic disease of the newborn, signs and symptoms may be similar to those listed above, but in more serious cases may also involve bleeding within the skull (intracranial).
A deficiency of vitamin K may be suspected when symptoms listed above appear in someone who is at an increased risk such as:
those who have a chronic condition associated with malnutrition or malabsorption
those who have been on long-term treatment with antibiotics; the antibiotics can kill the bacteria that aid in the production of vitamin K2 in the small intestine
seriously ill patients such as cancer or dialysis patients or those in intensive care units
Short-term treatment for vitamin K deficiency usually involves either oral supplementation or injections. Long-term or lifetime supplementation may be necessary for those with underlying chronic conditions.
Problems with high levels of natural forms of vitamin K (K1 and K2) have not been reported. These forms have low toxicity, even at high concentrations. However, water soluble vitamin K3 can be toxic if administered in large quantities. Also, K3 is known to cause hemolytic anemia in infants, so it is not used to treat the very young.
Vitamin K-dependent clotting factors are produced by the liver. If a person has chronic liver disease, they may not be able to produce sufficient clotting factors even when adequate vitamin K is available. Vitamin K supplementation may not be effective in those with seriously damaged livers.
Excellent sources of vitamin K include parsley, kale, spinach, Brussels sprouts, Swiss chard, green beans, asparagus, broccoli, kale, mustard greens, turnip greens, collard greens, thyme, romaine lettuce, sage, oregano, cabbage, celery, sea vegetables, cucumber, leeks, cauliflower, tomatoes, and blueberries.
Freezing foods may destroy vitamin K, but heating does not affect it.
In terms of health research, vitamin K is best known for its role in healthy blood clotting. In fact, use of the letter "K" in the very name of this vitamin originally came from the German word koagulation.
Although blood clotting may not sound like a body process that is critical for our everyday health, it is, in fact, essential. At one end of the spectrum, whenever we get a skin wound (even a simple cut) we need sufficient blood clotting ability to close the wound and prevent excessive bleeding. At the other end of the spectrum, we do not want too much blood clotting ability because when we are not wounded, we do not want our cardiovascular system to "throw a clot" and mistakenly block an otherwise functioning blood vessel. Vitamin K is one of the key nutrients for keeping our blood clotting ability at the exact right level.
Vitamin K is used to reduce the risk of bleeding in liver disease, conditions where your body doesn't absorb enough vitamin K, or if you take antibiotics for a long time.
In the U.S., Canada, Great Britain, and many other countries, all newborns receive vitamin K injections to prevent the possibility of bleeding, particularly in the brain. Babies are born without any bacteria in their intestines and do not get enough vitamin K from breast milk to tide them over until their bodies are able to make it.
Even though vitamin K deficiency in newborns is very rare, it is dangerous enough that doctors give the injections. Newborns at greatest risk for vitamin K deficiency are premature or those whose mother had to take seizure medications during pregnancy. Mothers on seizure medications are often given oral vitamin K for 2 weeks before delivery.
The relationship of vitamin K to bone health has been fairly well researched, and in the big picture, vitamin K has emerged as a critical nutrient for bone health. Most convincing is research showing protection from bone fractures that occurs when vitamin K is consumed in adequate amounts. Individuals who are vitamin K deficient have been clearly shown to have a greater risk of fracture. In addition, for women who have passed through menopause and have started to experience unwanted bone loss, vitamin K has been clearly shown to help prevent future fractures. These bone-related benefits of vitamin K appear to depend on at least two basic mechanisms.
The first of these mechanisms involves a type of bone cells called osteoclasts. Osteoclasts are bone cells in charge of bone demineralization -- they help take minerals out of the bone and make them available for other body functions. While the activity of these cells is important for proper health, we do not want too many osteoclasts (or too much activity by osteoclasts) since those imbalances would mean too much bone demineralization. Vitamin K makes it possible for our body to keep this process in check. One of the menaquinone forms of vitamin K (MK-4, also called menatetrenone) has repeatedly been show to block formation of too many osteoclasts and perhaps also to initiate their programmed cell death (a process called apoptosis).
A second mechanism involves the role of vitamin K in a process called carboxylation. (This process is the same one discussed earlier in relationship to the stickiness of clotting factors required for proper blood clotting.) For our bones to be optimally healthy, one of the proteins found in bone -- a protein called osteocalcin -- needs to be chemically altered through the process of carboxylation. (Osteocalcin is not just any typical bone protein. It is a protein especially linked to our bone mineral density (BMD) and for this reason, it is often measured in our blood when doctors are seeking to determine the health of our bone.) When too few of the osteocalcin proteins in our bone are carboxylated, our bones have increased risk for fracture. This unwanted risk appears to be particularly important with respect to hip fracture. Scientists refer to this bone problem as one involving -- undercarboxylated osteocalcin, -- and they have determined that vitamin K can greatly improve the situation. Since vitamin K is required for proper activity of the carboxylase enzyme that allows carboxylation of the osteocalcin proteins in our bone, vitamin K can restore these bone proteins to their proper place in our bone structure and strengthen the composition of the bone. It is the MK-4 menaquinone form of vitamin K that has been best researched in this regard.
One common problem in many forms of cardiovascular disease is unwanted calcification, the build-up of calcium inside a tissue that is normally soft. This build-up of calcium causes the tissue to harden and stop functioning properly. When calcium builds up inside the arteries, it is typically referred to as hardening of the arteries. One direct way to inhibit the build-up of calcium along the arteries is to maintain ample supplies of a special protein called MGP in the body. MGP, or matrix Gla protein, directly blocks the formation of calcium crystals inside the blood vessels. For MGP to function in this way, it must first be present in its carboxylated form; vitamin K is required for this carboxylation process. In other words, the heart-protective benefits of MGP in prevention of calcification depend upon vitamin K. In animal studies, both basic forms of vitamin K -- i.e., phylloquinones and menaquinones -- have been found to provide excellent calcification-preventing benefits. Researchers have determined that individuals with vitamin K deficiency are at greater risk for hardening of the arteries than individuals with healthy vitamin K intake.
Researchers continue to explore a wide range of health-supportive roles for vitamin K. At the forefront of this research are roles in three basic areas: (1) protection against oxidative damage; (2) proper regulation of inflammatory response; and (3) support of brain and nervous system structure. With respect to protection against oxidative damage, vitamin K does not appear to function directly as an antioxidant in the same manner that other antioxidant vitamins like vitamin E and vitamin C do. Yet, both phylloquinone and menaquinone forms of vitamin K appear helpful in protecting cells -- particularly nerve cells -- from oxidative damage. In terms of inflammatory response, several markers of pro-inflammatory activity -- including, for example, release of interleukin-6 (IL-6) -- are significantly lowered by healthy vitamin K levels. Finally, with regard to brain and nervous system structure, vitamin K is known to be required for synthesis of a very important family of brain and nervous system fats called sphingolipids. These fats are critical in the formation of the myelin sheath that forms an outer wrapping around the nerves, and both phylloquinone and menaquinone forms of vitamin K have been found effective in supporting synthesis of these key nervous system components. All of the above roles for vitamin K have been investigated primarily in laboratory studies on animals or in laboratory studies on human cell samples.
There are 3 forms of vitamin K:
Vitamin K1 or phylloquinone, the natural version of K1 and phytonadione, the synthetic type of K1
Vitamin K2 or menaquinone
Vitamin K3 or menaphthone or menadione
Vitamin K1 is the only form available in the U.S. as a supplement. It is available as part of multivitamin complexes or alone, in 5 mg tablets.
Water-soluble chlorophyll is the most common form of vitamin K found over the counter. It is available in tablet, capsule, and liquid forms.
As with all supplements, check with a health care provider before taking vitamin K or giving it to a child.
People whose bodies can't absorb enough vitamin K, because of gallbladder or biliary disease, cystic fibrosis, celiac disease, or Crohn's disease, will probably get more benefit from a multivitamin containing vitamin K than an individual vitamin K supplement. In certain circumstances, your doctor may give you a vitamin K shot.
The daily Adequate Intake for vitamin K is:
Pediatric
Infants birth - 6 months: 2 mcg
Infants 7 - 12 months: 2.5 mcg
Children 1 - 3 years: 30 mcg
Children 4 - 8 years: 55 mcg
Children 9 - 13 years: 60 mcg
Adolescents 14 - 18 years: 75 mcg
A single injection of vitamin K is also given at birth.
Adult
Men 19 years and older: 120 mcg
Women 19 years and older: 90 mcg
Pregnant and breastfeeding women 14 - 18 years: 75 mcg
Pregnant and breastfeeding women 19 years and older: 90 mcg
Minor side effects of vitamin K include upset stomach. At higher doses, vitamin K may trigger allergic reactions.
Although allergic reaction from supplementation is possible, there is no known toxicity associated with high doses of the phylloquinone (vitamin K1) or menaquinone (vitamin K2) forms of vitamin K and therefore no tolerable upper intake level (UL) has been set.
Blood clotting (coagulation) studies in humans using 45 mg per day of vitamin K2 (as MK4) and even up to 135 mg/day (45 mg three times daily) of K2 (as MK4), showed no increase in blood clot risk. Even doses in rats as high as 250 mg/kg body weight did not alter the tendency for blood-clot formation to occur.
However, a synthetic form of vitamin K, vitamin K3 (menadione), is demonstrably toxic. In fact, the FDA has banned this synthetic form of the vitamin from over-the-counter supplements because large doses have been shown to cause allergic reactions, hemolytic anemia, and cytotoxicity in liver cells.
Vitamin K is safe for most people. Most people do not experience any side effects when taking in the recommended amount each day.
When taken in the recommended amount each day, vitamin K is considered safe for pregnant and breast-feeding women, but don't use higher amounts without the advice of your healthcare professional.
People with a rare metabolic condition called Glucose-6-phosphate dehydrogenase (G6PD) deficiency should avoid vitamin K.
People who take warfarin (Coumadin) should not take vitamin K (see "Possible Interactions").
Too much vitamin K can be harmful if you are receiving dialysis treatments due to kidney disease.
Vitamin K is not effective for treating clotting problems caused by severe liver disease. In fact, high doses of vitamin K can make clotting problems worse in these people.
If you are currently being treated with any of the following medications, you should not take vitamin K without first talking to your health care provider.
Antibiotics -- Antibiotics, especially those known as cephalosporins, reduce the absorption of vitamin K in the body. Using them for more than 10 days may lower levels of vitamin K because these drugs kill not only harmful bacteria but also the bacteria that make vitamin K. People who already have low levels of vitamin K, such as those who are malnourished, elderly, or taking warfarin (Coumadin) are at greater risk. Cephalosporins include:
Cefamandole (Mandol)
Cefoperazone (Cefobid)
Cefmetazole (Zefazone)
Cefotetan (Cefotan)
Phenytoin (Dilantin) -- Phenytoin interferes with the body's ability to use vitamin K. Taking anticonvulsants (such as phenytoin) during pregnancy or while breastfeeding may lower vitamin K in newborns.
Warfarin (Coumadin) -- Vitamin K blocks the effects of the blood-thinning medication warfarin, so that it doesn't work. You should not take vitamin K, or eat foods containing high amounts of vitamin K, while you are taking warfarin.
Orlistat (Xenical, Alli) and Olestra -- Orlistat, a medication used for weight loss, and olestra, a substance added to some foods, lowers the amount of fat you body can absorb. Because vitamin K is a fat-soluble vitamin, these medications may also lower levels of vitamin K. The Food and Drug Administration now requires that vitamin K and other fat-soluble vitamins (A, D, and E) be added to food products containing olestra. Doctors who prescribe orlistat usually recommend taking a multivitamin with these vitamins. If you should not be taking vitamin K, then you should avoid foods that contain olestra.
Cholesterol-lowering medications -- Bile acid sequestrants, used to reduce cholesterol, reduce how much fat your body absorbs and may also reduce absorption of fat-soluble vitamins. If you take one of these drugs, your doctor may recommend a vitamin K supplement:
Cholestyramine (Questran)
Colestipol (Colestid)
Colsevelam (Welchol)
The following doses have been studied in scientific research:
BY MOUTH:
For bleeding disorders such as hypoprothrombinemia: 2.5-25 mg of vitamin K1 (phytonadione).
For counteracting bleeding that can occur when too much of the anticoagulant warfarin is given: 1-5 mg of vitamin K is typically used; however, the exact dose needed is determined by a lab test called the INR.
There isn't enough scientific information to determine recommended dietary allowances (RDAs) for vitamin K, so daily adequate intake (AI) recommendations have been formed instead: The AIs are: infants 0-6 months, 2 mcg; infants 6-12 months, 2.5 mcg; children 1-3 years, 30 mcg; children 4-8 years, 55 mcg; children 9-13 years, 60 mcg; adolescents 14-18 years (including those who are pregnant or breast-feeding), 75 mcg; men over 19 years, 120 mcg; women over 19 years (including those who are pregnant and breast-feeding), 90 mcg.
4-Amino-2-Methyl-1-Naphthol, Fat-Soluble Vitamin, Menadiol Acetate, Menadiol Sodium Phosphate, Menadione, Menadione Sodium Bisulfite, Menaquinone, Menatetrenone, Phytonadione, Methylphytyl Naphthoquinone, Phylloquinone, Phytomenadione, Vitamina K, Vitamine K.
The following reviews have been selected:
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5.0 out of 5 stars good source of K, helps with skin, October 3, 2011
By
matty crane
Noticed a marked improvement in my skin after trying this for a month. Good stuff all around. High dosage of pure vitamin K!
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2 of 2 people found the following review helpful:
5.0 out of 5 stars For Your Bones, November 2, 2011
By
Elinor Mavor...
If you have osteoporosis this product is an excellent source of Vitamin K2 (Menaquinone) which studies have shown to offer excellent help with this disease.
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11 of 12 people found the following review helpful:
5.0 out of 5 stars Saving your bones, April 9, 2010
By
Marilyn D. Kagan... (Providence, RI USA)
Have you started on the road to osteoporosis? Do you have trouble with taking calcium? This is a product that has no calcium, but if one takes it for a year, and has a Dexa scan to compare, will strengthen your bones without the dangers that calcium has for you personally. A cousin of mine took this for a year and her Dexa shows that her bones have strengthened. I have calcium absorption problems, so I ran to the computer and ordered these capsules. It's only a few weeks, so I'll have to order a few more jars, and see what happens after a year, but from what I've read, it should help a lot. The capsules are small, and taste sweet. That alone is an advantage!
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25 of 26 people found the following review helpful:
5.0 out of 5 stars Everyone should take this!, October 15, 2010
By
Jules Abramson (Warrenton, Virginia)
"The inverse association between heart disease and vitamin K2 intake is more straightforward. In The Rotterdam Study, which prospectively followed just over 4,600 men aged 55 or older in the Netherlands, the highest intake of vitamin K2 was associated with a 52 percent lower risk of severe aortic calcification, a 41 percent lower risk of coronary heart disease (CHD), a 51 percent lower risk of CHD mortality, and a 26 percent lower risk of total mortality. Even though the study population consumed ten times more K1 than K2, vitamin K1 had no association with either the degree of aortic calcification or the risk of heart disease. The profound effects of variations in such small amounts of dietary K2 emphasize just how powerful this substance is in the prevention of degenerative disease."
From the Weston A. Price Foundation quoting Chris Masterjohn
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29 of 31 people found the following review helpful:
5.0 out of 5 stars Vitamin K2 for your health, August 5, 2010
By
D. Mantelli... (Silicon Valley, CA USA)
Vitamin K2 is may help in with following:
-Blood clotting
-Prevention of Heart Disease and Arterial Plaque
-Enhance Bone Health and Prevent Osteoporosis
-Fight Cancer
-Boost the Immune System and Help Prevent the Signs of Aging
-May reduce the risk of type 2 diabetes
Vitamin K2 is best absorbed with food containing fat. The softgels are small and easy to swallow with no noticeable smell or taste.
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6 of 6 people found the following review helpful:
5.0 out of 5 stars Feeding your body at the cellular level, November 19, 2011
By
David M. Gordon (Summerlin, NV)
Taking vitamins and nutritional supplements are a fascinating exercise in negative feedback; that is, they prevent your body from breaking down from the ravages of age and oxidative stress. This means you will note their deficiency, but not their sufficiency. Compound this reality with the fact that, as of this writing, research labs cannot accurately measure levels of several crucial nutrients; Vitamin K is one of those unmeasurable but crucial bio-markers. Now add to the foregoing the fact that many supplements MUST be ingested in the proper form and dosage for maximum efficacy, and the consumer ends up as much confused as helped.
Which all explains why I appreciate Jarrow Formulas' products. Consider Jarrow's MK-7, the correct form of Vitamin K2... Ahh, you see, it is not so simple as just buying Vitamin K! You must know the differences between K1 and K2, and also the constituent parts of K2 (the form of K you want to supplement) to know that you (your body) seeks to replenish its store of MK-7. Jarrow does this work for you, and more.
So I will not make a claim I cannot support ("I feel better than I have in decades, thanks to this product") but I can say that taking MK-7 helps feed my body at the cellular level, and that, after much research, Jarrow's products rank among the best of breed.
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9 of 9 people found the following review helpful:
5.0 out of 5 stars excellent product for heart health, May 18, 2011
By
Mark Twain "John" (Georgia, USA)
this product seems to be on the cutting edge for the prevention of heart attack and heart disease
i run it every other morning with omega 3-6-9, Vitamin D and Calcium
since then, it seems like the occasional minor chest pains ive had for the last 20 years or so have reduced and/or stopped for the most part
if it can really keep the calcium out of your arteries, and onto your bones like the studies have shown, it is certainly something worth looking into
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