Menadione; Menaphthone; Menaquinone; Phylloquinone
Vitamin K is a fat-soluble vitamin, so your body stores it in fat tissue and the liver. It is best known for its role in helping blood clot, or coagulate, properly. The "K" comes from its German name, Koagulationsvitamin. Vitamin K also plays an important role in bone health.
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. Vitamin K deficiency can lead to excessive bleeding, which may begin as oozing from the gums or nose. 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
Other conditions that benefit from vitamin K include:
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.
Your body needs vitamin K to use calcium to build bone. People who have higher levels of vitamin K have greater bone density, while low levels of vitamin K have been found in those with osteoporosis. Similarly, some studies suggest that low levels of vitamin K are associated with a higher risk of osteoarthritis.
There is increasing evidence that vitamin K improves bone health and reduces the risk of bone fractures, particularly in postmenopausal women who are at risk for osteoporosis. In addition, studies of male and female athletes have also found that vitamin K helps with bone health. However, some studies have found that vitamin K didn’t help with bone density.
Foods that contain a significant amount of vitamin K include beef liver, green tea, turnip greens, broccoli, kale, spinach, cabbage, asparagus, and dark green lettuce. Chlorophyll is the substance in plants that gives them their green color and provides vitamin K.
Freezing foods may destroy vitamin K, but heating does not affect it.
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.
How to Take It
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:
- 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.
- 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
Because of the potential for side effects and interactions with medications, you should take dietary supplements only under the supervision of a knowledgeable health care provider.
At recommended doses, vitamin K has few side effects.
Vitamin K crosses the placenta and is also found in breast milk. Pregnant women and women who are breastfeeding should talk to their doctor before taking vitamin K supplements.
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”).
People who are receiving dialysis for kidney diseases can have harmful effects from too much vitamin K.
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. Speak with your physician for specific dietary guidelines.
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)
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Bugel S. Vitamin K and bone health in adult humans. Vitam Horm. 2008;78:393-416.
Crowther MA, Julian J, McCarty D, et al. Treatment of warfarin-associated coagulopathy with oral vitamin K: a randomized controlled trial. Lancet. 2000;356(9241):1551-1553.
Dennehy C, Tsourounis C. A review of select vitamins and minerals used by postmenopausal women. Maturitas. 2010 Aug;66(4):370-80. Review.
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McCormick RK. Osteoporosis: integrating biomarkers and other diagnostic correlates into the management of bone fragility. Altern Med Rev. 2007 Jun;12(2):113-45. Review.
Misra D, Booth SL, Tolstykh I, Felson DT, Nevitt MC, Lewis CE, Torner J, Neogi T. Vitamin K deficiency is associated with incident knee osteoarthritis. Am J Med. 2013;126(3):243-8.
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Shiraki M, Shiraki Y, Aoki C, Miura M. Vitamin K2 (menatetrenone) effectively prevents fractures and sustains lumbar bone mineral density in osteoporosis. J Bone Miner Res. 2000;15(3):515-523.
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|Life Stage||Recommended Amount|
|14–18 years||75 mcg|
|Adult men 19 years and older||120 mcg|
|Adult women 19 years and older||90 mcg|
|Pregnant or breastfeeding teens||75 mcg|
Vitamin K deficiency bleeding or VKDB, occurs when babies cannot stop bleeding because their blood does not have enough Vitamin K to form a clot. The bleeding can occur anywhere on the inside or outside of the body.What food is high in vitamin K? ›
- Green leafy vegetables including collard and turnip greens, kale, spinach, broccoli, Brussels sprouts, cabbage, lettuces.
- Soybean and canola oil.
- Salad dressings made with soybean or canola oil.
- Fortified meal replacement shakes.
Vitamin K toxicity is extremely rare. The only reported toxicity comes from menadione, which has no use in humans. Its toxicity is thought to be associated with its water-soluble properties. When toxicity does occur, it manifests with signs of jaundice, hyperbilirubinemia, hemolytic anemia, and kernicterus in infants.How much K2 and D3 should I take daily? ›
This means that usually most people will need to take between 5,000-8,000 IU (125 mcg-200 mcg) daily. Our Vitamin D3 (5000 iu) is our customers most common choice when supplementing with Vitamin D3. For vitamin K, at least 2.5 mg of a total vitamin K (including K1 and K2) should be taken daily.Can too much vitamin K cause blood clots? ›
Abnormal clotting is not related to excessive vitamin K intake, and there is no known toxicity associated with vitamin K1 or vitamin K2 (see Toxicity). Some oral anticoagulants, such as warfarin (Jantoven, formerly known as Coumadin), inhibit coagulation by antagonizing the action of vitamin K.Are bananas high in vitamin K? ›
Banana. This delicious fruit is packed with vitamin K and other essential nutrients that help with digestion and weight management. Vitamin K present in bananas is easily absorbed by the body and helps metabolise carbohydrates and fats, turning them into energy.Do I need to take vitamin K with vitamin D? ›
It's crucial that these vitamins be taken together because supplementing vitamin K with D helps the body use calcium properly to build bone instead of depositing it dangerously in arteries and soft tissue.How do you increase vitamin K absorption? ›
That's because vitamin K is fat-soluble and may be better absorbed when combined with fat. Vitamin K2 is only found in animal foods and certain fermented dishes. Small amounts are also produced by your gut bacteria ( 10 ).What are 4 signs of deficiency of vitamin K? ›
What are the symptoms of vitamin K deficiency? Not having enough vitamin K in the body makes you more likely to bleed. You may bruise more easily than usual, or it may be more difficult to stop bleeding after an injury or surgery. It can also make your periods heavier.
Eggs are the easiest to make and can be eaten for any meal of the day. This protein-rich food is also packed with vitamin K. One egg yolk contains anywhere in between 67 and 192 mcg of vitamin K2.How can I get K2 naturally? ›
Good sources of vitamin K-2 include fermented foods, organ meats, and dairy products. Fermented soybeans, such as natto, are an especially rich source of vitamin K-2. Bacteria that live in the human gut also produce small quantities of K-2. Both forms of vitamin K are essential for blood clotting and bone health.What fruit is high in vitamin K? ›
Vitamin K is found mostly in green vegetables and some fruits. Green leafy vegetables such as collards, spinach, broccoli, Brussels sprouts, and cabbage contain vitamin K. Some fruits such as kiwi, blackberries, and blueberries are also rich in vitamin K.Can too much vitamin K cause a stroke? ›
Additionally, one paper has identified the possibility of an association between a genetic predisposition for higher serum levels of vitamin K and a higher incidence of stroke .Who should not take vitamin K? ›
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”). People who are receiving dialysis for kidney diseases can have harmful effects from too much vitamin K.How much K2 is in an egg? ›
An egg yolk can contain between 67 and 192 micrograms of vitamin K2. This amount depends on what the hen eats, however. Most chicken feed today is fortified with vitamin K, and this content passes onto the egg.Should I take vitamin D3 K2 in the morning or at night? ›
There's no set time of day that's best to take vitamin D supplements. Some people say taking vitamin D supplements at night is an insomnia risk. There's no research to confirm this, but you might want to take your supplement earlier in the day if you think it's screwing with your sleep.What vitamins should you not take together? ›
- Magnesium and calcium/multivitamin. ...
- Vitamins D, E and K. ...
- Fish Oil & Gingko Biloba. ...
- Copper and zinc. ...
- Iron and Green tea. ...
- Vitamin C and B12.
In a new study, scientists have presented powerful evidence that vitamin K2 can reduce the progression of atherosclerosis, the “blockage” of the arteries that can lead to heart attacks and strokes.Does vitamin K2 thicken or thin the blood? ›
Aids in blood clotting
One of the main functions of K vitamins is to allow your blood to clot. In fact, the “K” in vitamin K is in reference to the German word “koagulation,” which translates to “coagulation” or the ability to clot (or thicken) blood.
Side effects of vitamin K excess include enlarged liver, paleness, increased sweating, shortness of breath, muscle stiffness, edema, irregular breathing, decreased movement or activity, swollen eyelids, or red skin.Are avocado high in vitamin K? ›
Fruit isn't uber-rich in vitamin K, but certain ones can give you a quick burst of it. A cup of sliced avocado can give you up to 50 micrograms of vitamin K.Is there vitamin K in coffee? ›
Does coffee have vitamin K? A. No, coffee does not have vitamin K. However, a 100 g cup of coffee has 355 calories with 0 g total fat and cholesterol.Which vegetable has most vitamin K? ›
- cooked spinach – 540.7 mcg.
- cooked kale – 418.5 mcg.
- cooked mustard greens – 592.7 mcg.
- cooked collard greens – 623.2mcg.
- cooked beet greens – 484 mcg.
- raw swiss chard – 830 mcg.
- raw dandelion greens – 778.4 mcg.
- cooked turnip greens – 518.9 mcg.
Vitamin D3 should therefore always be taken in combination with vitamin K2. These two vitamins work together synergistically and ensure that calcium obtained from food is deposited in the bones and not in the arteries.Can Vitamin D3 and K2 have side effects? ›
Constipation. Change in color of stool to green. Diarrhea. Belly pain.Can you take too much Vitamin D3 and K2? ›
While getting enough vitamin D is essential for bone health, too much can actually have a detrimental effect. Some research has found that having too much vitamin D can interfere with the actions of vitamin K2, which is a nutrient that helps keep calcium in the bones.Can you get enough vitamin K from food? ›
The most common sources of vitamin K in the U.S. diet are spinach; broccoli; iceberg lettuce; and fats and oils, particularly soybean and canola oil [5,7].Does olive oil have vitamin K? ›
The other main vitamin found in extra virgin olive oil is Vitamin K, with about 10% of the recommended daily intake of Vitamin K in 1 tablespoon of olive oil. Research shows that Vitamin K is an important nutrient to aid in blood clotting.Which nuts are high in vitamin K? ›
With the exception of pine nuts and cashews, which contain 53.9 and 34.8 microg of phylloquinone per 100 g of nut, respectively, nuts are not important dietary sources of vitamin K. Similarly, most fruits are not important sources of vitamin K, with the exception of some berries, green fruits, and prunes.
Adults should ensure they are getting between 100 and 300 micrograms of vitamin K2 per day. Children under 12 need just 45 micrograms per day. People with particular medical conditions may need more, as recommended by their doctor. There are no known serious side effects from taking too much vitamin K2.How much vitamin K2 do you need a day? ›
To ensure a healthy heart and prevent complications due to calcification, a daily intake of at least 32mcg of vitamin K2 should be ingested through one's diet.How much K2 is needed with D3? ›
How much K2 should I take with D3? Taking a Vitamin D3 supplement without K2 can have disastrous effect, as Vitamin D creates need for Vitamin K2 in the body. As a guide, you should take 45mcg of Vitamin K2 per 1000 IU of Vitamin D3.Should I take D3 and K2 at same time? ›
Vitamin D3 should therefore always be taken in combination with vitamin K2. These two vitamins work together synergistically and ensure that calcium obtained from food is deposited in the bones and not in the arteries.How much vitamin K2 to clear arteries? ›
A subgroup analysis of the study observed that vitamin K2 MK-7 (720 µg/day) and D (25 µg/day) supplementation for two years helped slow the progression of coronary plaque development in individuals at high risk of developing coronary artery calcification with no prior identified ischemic heart disease.How much K2 is in one egg? ›
An egg yolk can contain between 67 and 192 micrograms of vitamin K2.Who should not take K2 vitamin? ›
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”). People who are receiving dialysis for kidney diseases can have harmful effects from too much vitamin K.What vitamin should not be taken with vitamin K? ›
Some studies suggest that the body may not be able to absorb vitamin K as efficiently when taken with vitamins D and E. As a result, taking a large dose of these three vitamins together may prevent vitamin K from clotting the blood effectively .What is the best source of K2? ›
Vitamin K2 is mainly found in certain animal and fermented foods, which most people don't eat much of. Rich animal sources include high fat dairy products from grass-fed cows and egg yolks, as well as liver and other organ meats ( 22 ).How do you know if you need vitamin K2? ›
Since vitamin K is responsible for blood clotting, a vitamin K2 deficiency manifests itself in very heavy bleeding in injuries. Vitamin K2 deficiency is also noticeable through nosebleeds, bleeding of the mucous membranes and bruises. In the case of a vitamin K2 deficiency, bruises can be caused by a slight pressure.
You should be able to get all the vitamin K you need by eating a varied and balanced diet. If you take vitamin K supplements, do not take too much as this might be harmful. Taking 1mg or less of vitamin K supplements a day is unlikely to cause any harm.What happens when you start taking vitamin K2? ›
When you take Vitamin K2, it helps your body to produce more of the protein needed for blood clotting. It also helps to keep your bones healthy by keeping calcium in your bones and out of your arteries. Vitamin K2 is also essential for heart health because it helps prevent the arteries from hardening.What happens if you take too much vitamin D3 and K2? ›
The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination. Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones.Can you take too much vitamin D3 and K2? ›
While getting enough vitamin D is essential for bone health, too much can actually have a detrimental effect. Some research has found that having too much vitamin D can interfere with the actions of vitamin K2, which is a nutrient that helps keep calcium in the bones.