Vitamin K
By Dietitian, Juliette Kellow BSc RD
How much you need each day:
There’s no RNI. A safe intake is considered to be 1mcg per kilogram of body weight.
For example, a person who weighs 70kg will need about 70mcg of vitamin K each day.
Why you need it:
Vitamin K helps the blood to clot after a cut or injury.
Unlike most of the other vitamins, which need to be supplied by the diet, about half of the vitamin K we get is made in the large intestine by bacteria.
Good food sources:
As well as being made in the body, foods containing vitamin k include green leafy vegetables, liver, milk, vegetable oils, wholegrains, oats and meat.
Too little:
As our bodies make vitamin K, a deficiency is rare but may occur in people who are given drugs that destroy gut bacteria, for example, prolonged use of antibiotics.
A deficiency can cause easy bruising and a prolonged bleeding time after an injury.
Babies are given an injection of vitamin K when they’re born as their gut is free of bacteria and breast milk doesn’t contain much of this vitamin.
Top tip:
Probiotic drinks and yoghurts that contain acidophilus bacteria help to boost levels of gut bacteria, ensuring you make enough vitamin K.
If you are taking a course of antibiotics, it’s a good idea to include products like these in your diet, as some drugs can inhibit the absorption of this vitamin.
How to get enough:
Food | Vitamin K Content (mcg) |
---|---|
90g steamed spinach | 216 |
90g boiled broccoli | 90 |
90g boiled cabbage | 90 |
150g lean grilled pork chop | 17 |
300ml semi-skimmed milk | 12 |
50g oats | 10 |
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