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

Start a Free Trial Today

You can follow a healthy, balanced diet using the food diary and database tools in Weight Loss Resources. Try it free for 24 hours.

Take our FREE trial »

Lose a Stone for Christmas Challenge

If you enjoyed this article, try our newsletter. It's free.

Receive the latest on what works for weight loss straight to your inbox. We won't share your email address. Privacy policy