Skip to main contentSkip to main content

Vitamin K

Vitamin K is a group of vitamins that the body needs for blood clotting, helping wounds to heal.

There's also some evidence vitamin K may help keep bones healthy.

Vitamin K is found in:

  • green leafy vegetables – such as broccoli and spinach
  • vegetable oils
  • cereal grains

Small amounts can also be found in meat and dairy foods.

Adults need approximately 1 microgram a day of vitamin K for each kilogram of their body weight.

For example, someone who weighs 65kg would need 65 micrograms a day of vitamin K, while a person who weighs 75kg would need 75 micrograms a day.

A microgram is 1,000 times smaller than a milligram (mg). The word microgram is sometimes written with the Greek symbol μ followed by the letter g (μg).

You should be able to get all the vitamin K you need by eating a varied and balanced diet.

Any vitamin K your body does not need immediately is stored in the liver for future use, so you do not need it in your diet every day.

There's not enough evidence to know what the effects might be of taking high doses of vitamin K supplements each day.

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.