Vitamin K has several important functions. For example, it is needed for blood clotting, which means it helps wounds heal properly.
There is increasing evidence that vitamin K is also needed to help build strong bones.
Good sources of vitamin K
Vitamin K is found in:
- green leafy vegetables, such as broccoli and spinach
- vegetable oils
Small amounts can also be found in meat and dairy foods.
How much vitamin K do I need?
Adults need approximately 0.001mg a day of vitamin K for each kilogram of their body weight.
For example, someone who weighs 65kg would need 0.065mg a day of vitamin K, while a person who weighs 75kg would need 0.075mg a day.
You should be able to get all the vitamin K you need by eating a varied and balanced diet.
Any vitamin K that 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.
What happens if I take too much vitamin K?
There is not enough evidence to know what the effects might be of taking high doses of vitamin K supplements each day.
What does the Department of Health advise?
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 because this might be harmful.
Taking 1mg or less of vitamin K supplements a day is unlikely to cause any harm.