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All you need to know about Vitamin K

If you cut your hand while slicing vegetables, you probably just shrug it off and continue. Because we know that the blood will clot and the wound will heal eventually. But have you wondered what would have happened if we never stopped bleeding? Luckily- that is one nightmare we never have to be in. And all that is due to this miraculous thing called vitamin K. Want to know more about it? Read on.

What is Vitamin K?

Vitamin K helps blood with clotting and lets the bones grow the way they should be. The name Vitamin K is derived from the German word “Koagulationsvitamin.” But did you know that Vitamin K includes two natural vitamins? These are vitamin K1 and vitamin K2. Vitamin K2, in turn, consists of several related chemical subtypes.

Vitamin K1, also known as phylloquinone, phytomenadione, or phytonadione, is synthesized by plants and is found in the highest amounts in leafy green vegetables. It is directly involved in photosynthesis. One may call this as the “plant” form of vitamin K. Vitamin K1 is active as a nutrient in animals and performs the classic functions of vitamin K- including its activity in the production of blood-clotting proteins. Animals may also convert it to vitamin K2. (6)

Vitamin K2, the main storage form in animals, has several subtypes, which differ in the isoprenoid chain length. These vitamin K2 homologs are called menaquinones and are characterized by the number of isoprenoid residues in their side chains. (6)

What is the daily recommended dose of Vitamin K?

All of us need an adequate amount of Vitamin K in our daily diet to help blood clotting and healthy maintenance of bones. It is important to note that in case you are consuming warfarin, a blood thinner, you need to consult your health care provider to compensate for the amount of Vitamin K in your body. As per the daily recommendations, you should consume Vitamin K according to your age and gender. We have compiled the below-mentioned data to help you understand this better- (3)

Life StageRecommended Amount
Birth to 6 months2.0 mcg
7–12 months2.5 mcg
1–3 years30 mcg
4–8 years55 mcg
9–13 years60 mcg
14–18 years75 mcg
Adult men 19 years and older120 mcg
Adult women 19 years and older90 mcg
Pregnant or breastfeeding teens75 mcg
Pregnant or breastfeeding women90 mcg

Vitamin K sources

Some of the best sources of vitamin K are:

1. Spinach and other vegetables

Your mother is absolutely right when she insists you to have more green leafy vegetables in your diet. Among all the Indian green leafy vegetables, spinach tops the chart. This, along with collard green and kale is a rich storehouse of Vitamin K.

  • Half a cup of cooked kale gives you 531 mg of Vitamin K. (1)
  • You may want to indulge in raw spinach or mix it in your smoothie, as it provides you 75 mg of Vitamin K. (1)
  •  Roasted Brussels sprouts (1)
  •  Broccoli (1)
  • scallions (1)
  • frozen asparagus (1)
  • okra (1)
  • raw watercress (1)
  • green cabbage (1)
  • Adding ten sprigs of parsley to any of your meals can drastically boost the level of Vitamin K in your body. (1)

2. Fruits

Fruits may not always act as a rich source of Vitamin K. However, some of them may help you get that extra dose of the vitamin.

  • One cup of sliced avocado gives you 50 mg of Vitamin K. (1)
  • Half a cup of stewed prunes can give you 32 mg. (1)
  • 1/2 a cup of blueberries can you give you 14 mg of Vitamin K. (1)
  • Half a cup of grapes provides you 11 mg of Vitamin K. (1)
  • Apples give you 5 mg of Vitamin K. (1)

3. Oils

Soybean oil along with Canola oil serves as good sources of Vitamin K.

  • A spoon of Soybean oil gives you 25 mg of the vitamin. (1)
  • A spoon of Canola oil gives you 10 mg. (1)

4. Nuts

Besides fruits and vegetables, nuts are considered to be essential nutrients for our bodies.

  • Nuts such as cashews, pine nuts, or mixed nuts provide protein, fiber and essential healthy oils to our bodies. (1)
  • A handful of pine nuts added to our diet can increase Vitamin K levels in our body. (1)

5. Fish

The American Heart Association recommends including fish like salmon in our diet every day.

  • Canned tuna in the oil gives 37 mg per 3 ounces serving of Vitamin K.  (1)

6. Fresh juices and other sources

  • 3/4 cup of carrot juice can give you 28 mg of Vitamin K. (1)
  • A quarter cup of pomegranate juice gives you 19 mg of the vitamin. (1)
  • Just 3 ounces of the traditional Japanese dish, Natto gives you 850 mg of Vitamin K. This is a boiled and fermented soybean dish. Medical researches also show Natto reduces the loss of bone mass in women post their menopause. This also means it helps prevent osteoporosis. (1)

Effects of cooking procedures on Vitamin K

Your cooking procedures determine the amount of Vitamin K your body gets. For instance, cooked frozen foods contain more Vitamin K than raw ones. Half a cup of frozen turnips gives you 425 mg of the vitamin which is greater than the raw ones. (1)

The charts enumerated below will give a wider perspective about all the Vitamin K rich foods: (2)

Foods high in Vitamin K (more than 800 mg per serving)

FoodPortion Size
Kale1 cup
Spinach (frozen, chopped, cooked, boiled, or drained)1 cup
Collards1 cup
Turnip greens1 cup

Food sources that are high in Vitamin K (400-800 mg per serving)

FoodPortion Size
Beet greens1 cup
Dandelion greens1 cup
Mustard greens1 cup

Food sources that are moderately high in Vitamin K (80-400 mg per serving)

FoodPortion Size
Spinach (raw, leaf)1 cup
Brussel sprouts1 cup
Broccoli1 cup
Onions (springs or scallions, tops, and bulb)1 cup
Lettuce (iceberg)1 head
Lettuce (green leaf)1 cup
Cabbage1 cup
Asparagus1 cup
Parsley10 sprigs
Okra1 cup

Some more sources of Vitamin K

Food sourceServing sizeVitamin K content (mcg/per)
Herbs1 tbsp. of Dried Basil36 mcg
Greens½ Cup444 mcg
Spring Onions½ Cup103 mcg
Brussels Sprouts100 gm140 mcg
Broccoli100 gm140 mcg
Turnip Greens100 gm484 mcg
Spinach100 gm483 mcg
Mustard Greens100 gm593 mcg
Kale100 gm387 mcg
Parsley100 gm483 mcg
Pickled Cucumber100 gm130 mcg
Prunes100 gm60 mcg
Asparagus100 gm91 mcg
Chili Powder2.66 tbsp.22.5 mcg
Paprika100 gm80.3 mcg
Chicken100 gm60 mcg
Egg Yolk100 gm34 mcg
Pomegranate100 gm16 mcg
Blueberries100 gm19 mcg
Cashews100 gm34 mcg

Source (7)

Vitamin K2 food sources

It is good to note here that Vitamin K2 is mostly available in animal products and fermented plant-based sources. Some of the top Vitamin K2 food sources are- (7)

Food sourceServing sizeVitamin K content (mcg/per)
Beef liver100 gm106 mcg
Pork Chops100 gm69 mcg
Chicken100 gm60 mcg
Goose liver paste100 gm369 mcg
Bacon100 gm35 mcg
Ground Beef100 gm9.4 mcg
Pork liver100 gm7.8 mcg
Duck breast100 gm5.5 mcg
Beef Kidney100 gm5.7 mcg
Chicken liver100 gm13 mcg

Besides, there are some dairy products and nuts that provide a rich source of Vitamin K, though their contribution is lesser than plants. Here is the list- (7)

Food sourceVitamin availableServing sizeVitamin K content (mcg/per)
Hard CheesesVitamin K2100 gm87 mcg
Jarlsberg CheeseVitamin K2100 gm80 mcg
Soft CheesesVitamin K2100 gm59 mcg
Edam CheeseVitamin K2100 gm49 mcg
Blue CheeseVitamin K2100 gm36 mcg
Egg YolkVitamin K2100 gm34 mcg
CheddarVitamin K2100 gm13 mcg
Whole milkVitamin K2100 gm1.3 mcg
ButterVitamin K2100 gm21 mcg
CreamVitamin K2100 gm9 mcg
Green beansVitamin K100 gm48 mcg
Green peasVitamin K100 gm26 mcg
SoybeansVitamin K100 gm33 mcg
Sprouted Moong BeansVitamin K100 gm23 mcg
Red kidney beansVitamin K100 gm8.4 mcg
HazelnutsVitamin K100 gm14 mcg
Pine nutsVitamin K100 gm54 mcg
PecansVitamin K100 gm3.5 mcg
WalnutsVitamin K100 gm2.7 mcg


Physiological Function of Vitamin K

Vitamin K is a fat-soluble vitamin that primarily acts as a cofactor in blood coagulation and bone matrix proteins. Vitamin K is required for several vital physiological functions in the body including coagulation and bone metabolism. It is a fat-soluble vitamin that is absorbed through dietary intakes and also produced by “friendly” gut bacterias. (6)

Health concerns due to Vitamin K deficiency

1. Delay in blood clotting

Vitamin K deficiency results in an increase in the time required for blood to clot. The usual clinical manifestation is a tendency to hemorrhage. The measurement of prothrombin time in plasma reveals how it is dependent on vitamin K and other factors that help in the clotting of blood. (6)

2. Inadequate dietary intakes and fat malabsorption

Vitamin K status is especially important in the elderly because of inadequate dietary intakes and difficulties in the absorption of fat-soluble nutrients. This condition is further aggravated by frequent drug therapies. (6)

3. Poor bone health

Monitoring vitamin K levels in the body can help reduce bone fractures caused due to osteoporosis. This can be done by identifying individuals whose bone loss is due to vitamin K deficiency. The loss of calcium levels in such cases can be reduced by up to 50% with vitamin K supplementation. (6)

4. Other concerns

You may have a tendency to experience uncontrolled bleeding in the case of Vitamin K deficiency. But adults rarely face the deficiency, it is more common among newborn babies. Usually, in such cases, doctors advise a single injection of 10 mg Vitamin K as a standard practice. Though Vitamin K deficiency is a rarity in adults, people who have the following conditions are at a higher risk of experiencing a deficiency- (10)

  • Individuals with Crohn’s disease or Celiac disease
  • Individuals who consume drugs that interfere with Vitamin K absorption in the body
  • Those who are severely malnourished
  • Those who drink alcohol heavily

In these conditions, your medical practitioner would recommend Vitamin K supplements. (10)

Benefits of Vitamin K

1. Prevents hemorrhagic disease

Administering Vitamin K1 orally or through injection into the muscles can prevent any form of blood loss in newborns. (4)

2. Treat or prevent blood loss in case of absence of prothrombin

Some people lose the blood-clotting protein prothrombin due to certain medications. In such a scenario consuming Vitamin K1 orally or administering it through injections into veins can help prevent blood loss in these patients. (4)

3. Prevent blood loss in VKCFD

Taking Vitamin K through the mouth or through injections intravenously can help prevent blood loss due to a hereditary condition called Vitamin k-dependent clotting factors deficiency. (4)

4. Stabilizing blood clotting when using blood thinners/anticoagulants

A combination of Vitamin K and Warfarin helps in stabilizing blood clotting in those who have Vitamin K deficiency. (4)

5. Helps in blood clot

Vitamin K is one of the 13 main essential nutrients that help in blood clotting. Patients who consume anticoagulant medicines often need Vitamin K to counter the effects of these. Those who are on Warfarin need a consistent dose of Vitamin K either through their food or supplements as prescribed by the doctor. (5)

6. Maintain bone health

Vitamin K produces important proteins like osteocalcin in the bones. This helps in strengthening the bones. Hence medical experts prove that patients who take a higher dose of Vitamin K prevent hip fracture and low bone density. (5)

7. Role in preventing heart disease

Some studies show that Vitamin K helps in overall heart health. According to these studies, Vitamin K helps in the production of matrix Gla proteins (MGP). These proteins prevent calcification or hardening of the arteries. However, we are still awaiting further research in this area. (5)

Vitamin K Supplementation

Researches show very little data on the availability of the various forms of vitamin K supplements. The suggested dose for adult repletion of Vitamin K is 500-1000 mcg/day. (6)

Some of the Vitamin K supplements that can be listed are as follows-

1. Multivitamin/Multimineral

  • Most multivitamin or multimineral supplements at values less than 75% of the DV contain Vitamin K. This vitamin is also available in dietary supplements containing only vitamin K or vitamin K with a few other nutrients, commonly calcium, magnesium, and/or vitamin D. These supplements tend to have a wider range of vitamin K doses than multivitamin/mineral supplements, with some of them providing 4,050 mcg (5,063% of the DV). (7)

2. Vitamin K1 and Vitamin K2 supplements

  • A lot of Vitamin K supplements are in use. Some of them include vitamin K1 as phylloquinone or phytonadione (a synthetic form of vitamin K1) and vitamin K2 as MK-4 or MK-7. One of the studies suggests both phytonadione and MK-7 supplements being well absorbed, with the latter having a longer half-life. (7)

3. Vitamin K3 supplement

  • Another synthetic form of Vitamin K is Menadione or Vitamin K3. However, it showed damaging effects on hepatic cells when researches conducted laboratory experiments in the 1980s and 1990s. So one cannot consider this as one of the fortified sources. (7)

Side effects of Vitamin K

Both the forms of Vitamin K supplements, that are Vitamin K1 and Vitamin K2 are safe. But it is advisable that you should always consider the prescription by your health care experts before consuming Vitamin K orally or taking it intravenously through injections. You will not have any side effects if you adhere to the dosage as mentioned by your doctor. Some people who need to take precautions while using Vitamin K supplements are- (8)

  • Pregnant and lactating mothers. (8)
  • Children. (8)
  • Diabetic patients. (8)
  • Those with kidney and liver ailments. (8)
  • Individuals who have reduced bile secretions. (8)

Interactions of Vitamin K with other drugs

The most common advice is you must not take Vitamin K supplements unless prescribed by your health care provider. The main reason behind this is doctors rarely advise oral supplements for Vitamin K, hence you should adhere to the dosage strictly. Though the side effects of this vitamin are uncommon, it reacts with certain drugs. These can be listed as-

  • Warfarin or Coumadin or any other blood thinner as they are called Vitamin K antagonists. (9)
  • Antacids. (9)
  • Antibiotics. (9)
  • Aspirin. (9)
  • Medicines prescribed for cancer, seizures, high cholesterol, and other health conditions. (9)

Causes and Symptoms of Vitamin K deficiency

Vitamin K deficiency primarily occurs in the elderly primarily due to inadequate dietary intake and absorptive difficulties, frequently complicated by drug therapies.

Further, the common causes of Vitamin K deficiency in adults are-

  • When you are consuming anticoagulants. (11)
  • Being on antibiotics. (11)
  • In a situation when you suffer from a condition called fat malabsorption. It is the condition when your body cannot absorb fats properly. Vitamin K is a fat-soluble vitamin and hence due to this condition you are unable to absorb the same. (11)
  • When your diet lacks Vitamin K. (11)
  • Cystic fibrosis also lowers the level of Vitamin K in your body. (11)
  • When a part of your intestine is removed. (11)
  • When you suffer from disorders related to the liver, gallbladder or bile ducts. (11)

The causes of Vitamin K deficiency in infants are-

  • The breast milk being fed to the infant is low in Vitamin K. (11)
  • The mother’s placenta fails to transfer an adequate amount of Vitamin K to the fetus. (11)
  • The infant’s liver fails to absorb Vitamin K. (11)
  • Newborns do not produce enough Vitamin K2 in the first few days post their birth. (11)

These are the primary reasons as to why the American Academy of Pediatrics recommends a single dose of 0.5 mg to 1.0 mg of Vitamin K to be administered intramuscularly immediately after the birth of a newborn, in order to avoid VKDB or Vitamin K Deficiency Bleeding. (11)

Symptoms of Vitamin K Deficiency

The common signs of Vitamin K deficiency that you must report to your doctor are-

  • Frequent and easy bruising. (12)
  • Discharge from nose or gums. (12)
  • Prolonged excessive bleeding from wounds, ruptures and surgical areas. (12)
  • Heavy menstrual flow. (12)
  • Bleeding from the gastrointestinal tract. (12)
  • Frequent blood in urine or stool. (12)
  • Increased prothrombin time or late blood clotting. (12)
  • Osteopenia or Osteoporosis  (12)


Vitamin K is a vital nutrient that helps in overall bodily functions. Its primary aim is aiding blood clotting. Thus it is extremely essential for you to maintain a Vitamin K rich diet; in case you are on medication that interferes with Vitamin K levels, you must seek medical advice to either compensate for the loss with dietary supplements or replenish your diet with important food sources.

Author Anupama Singh

I am the founder of Vitsupp and have a bachelors in engineering. My family suffers from every lifestyle disease you can think of. Heart disease, obesity, high blood pressure, diabetes, hypothyroidism . . you name it and some one in my family has it. Trying to save myself and my family from our genetic disposition, I learnt much about nutrition, exercise and lifestyle diseases. Certificate in "Diabetes – The Essential Facts" by University of Copenhagen

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