Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

beginning of content

Vitamin K deficiency

3-minute read

Vitamin K deficiency is not common in adults, but can be serious because it stops the blood clotting properly. It can also make bones weaker, and increase a person’s chances of breaking them.

Why is vitamin K important?

Vitamin K is important because it helps your liver make proteins that help blood to clot. It is also important for healthy bones.

Adults usually have enough vitamin K because the normal bacteria in your gut produce it. It is also in the fat of much of the food that we eat. Vitamin K is stored in the liver, so you don’t need a lot of it every day.

See this separate article for important information on babies and vitamin K.

Vitamin K deficiency symptoms

Not having enough vitamin K in your body can make you bruise more easily than usual. It will be more difficult to stop bleeding after an injury or surgery. It can also make your periods heavier.

What causes vitamin K deficiency?

Most adults with vitamin K deficiency have a serious health problem such as:

Anticoagulants such as warfarin might increase your risk of vitamin K deficiency. 

Vitamin K deficiency diagnosis 

If your doctor suspects you have vitamin K deficiency, they may ask you to have a blood test to confirm it.

  • Some pathology services and hospitals measure vitamin K levels directly.
  • If that is not possible, you can have a blood test to check how well your blood clots. Next, you have an injection of vitamin K and your clotting is checked again. If your clotting improves after the injection, then you have a vitamin K deficiency.

You might also have other tests if there are other issues to investigate.

Preventing vitamin K deficiency

Most people get enough vitamin K in their diet. The best source is dark green leafy vegetables like spinach, parsley, broccoli, kale, cabbage, brussels sprouts and salad greens.

Green beans, avocados, kiwifruit, vegetable oils, yoghurt, fermented food and drinks, and some cheeses are also good sources.

Vitamin K deficiency treatment

If you do not have enough vitamin K, you’ll be asked to eat more of the foods listed above. It may help if you see a dietitian.

Your doctor might also prescribe vitamin K supplements. They can help your blood clot, and they might help increase bone strength. But don’t take them without talking to your doctor first since they can interfere with some other medicines. You should also avoid taking more than your doctor recommends since this might be harmful.

When to seek help

You should see your doctor if:

  • bleeding continues for longer than normal
  • you bruise easily
  • you break a bone after only a very minor fall or injury.

Last reviewed: May 2018

Need more information?

These trusted information partners have more on this topic.

Top results

Vitamin K at birth

Babies do not get enough vitamin K from their mothers during pregnancy, or when they are breast feeding. Without vitamin K, they are at risk of getting a rare disorder called ‘vitamin K deficiency bleeding’ (VKDB).

Read more on Women's and Children's Health Network website

Vaccination and Vitamin K Information | Queensland Health

Vitamin K is necessary to help blood clot and is essential to prevent serious bleeding.

Read more on Queensland Health website

Vitamin K at birth

Trusted information on the vitamin K injection at birth including why it is important, who can have it, side effects, plus links to trusted resources.

Read more on Pregnancy, Birth & Baby website

Vitamin K | Osteoporosis Australia

Vitamin K is essential for many processes in the body, including the maintenance of the skeleton.

Read more on Osteoporosis Australia website

Vitamin K and newborn babies - Better Health Channel

With low levels of vitamin K, some babies can have severe bleeding into the brain, causing significant brain damage.

Read more on Better Health Channel website

Vitamin K for newborn babies - Information for parents (2010) | National Health and Medical Research Council

Read more on NHMRC – National Health and Medical Research Council website

Kids' Health - Topics - More about vitamins

All plants and animals need vitamins but only plants can make all the vitamins they need. Humans can make vitamin D, using sunlight, and Niacin (say ny-ass-in) from an amino-acid in protein called tryptophan (say trip-toe-fan). Vitamin K is made by bacteria (germs) inside our gut. These germs are useful to have! We have to get all the other vitaminsfrom our food.

Read more on Women's and Children's Health Network website

Bleeding disorders - Lab Tests Online AU

Site map of article content

Read more on Lab Tests Online website

Pregnancy - Pregnancy Topics - When your baby is born the second and third stage

The second stage of labour starts when your cervix is fully dilated and you will usually soon have a strong urge to push because of the pressure your baby is placing on your pelvic area. This is the time to push your baby out.

Read more on Women's and Children's Health Network website

Baby’s first 24 hours

The first day of your new baby’s life is thrilling and exhausting for both of you. There is a lot going on in the first 24 hours, so find out what you can expect.

Read more on Pregnancy, Birth & Baby website

Healthdirect 24hr 7 days a week hotline

24 hour health advice and information you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Government of South Australia, health department logo Tasmanian government logo Government of Western Australia, health department logo
Feedback