Vitamin K

What is vitamin K?

Vitamin K is a fat-soluble vitamin, like vitamins A, E and D.  There are two main forms of vitamin K in foods – K1 and K2.  Vitamin K1 is found mainly in green leafy vegetables such as spinach and parsley and ‘brassicas’ such as broccoli and cabbage.  Vitamin K2 is found mainly in fermented foods: yoghurt, milk and fermented cheeses ...Read more are reasonably good sources, as well as egg yolks and some meats.  The Japanese food ‘natto’ is the richest source.

What does it do in the body?

The most well known role of vitamin K is in blood clotting – K1 is mainly responsible for this.  Vitamin K2 is thought to be more specifically helpful for the distribution of calcium in the body:  helping to bind calcium into the bones and preventing deposits of calcium in the arteries (which can lead to hardening of the arteries).

Other roles may include:
•    Supporting the immune system
•    Joint health (through preventing bone degradation)
•    Preventing tooth decay (through binding calcium into the teeth)
•    Energy production – through its role in the production of the body’s ‘energy molecule’ – ATP
•    Vitamin K cream applied topically may help to reduce or clear scarring, spider veins and bruising.

Do we need vitamin K supplements?

Most people are likely to consume enough vitamin K to ensure normal blood clotting.  However some people may not have enough of the K2 form to ensure that calcium is going to the right places in the body – this may be the case particularly for someone who avoids dairy and other animal foods, as these are the main sources.  

For this reason, anyone who has immediate concerns about their bone health, or their heart and arterial health, may be advised to take a supplement that includes may be advisable.  More specifically, it should contain the form of K2 known as menaquinone 7 or “MenaQ7”.  This is thought to be the most effective form of K2.

How can I take vitamin K?

As mentioned above, look for a vitamin K supplement that contains the MenaQ7 form of K2.  This can be found on its own or in a complex with other forms of vitamin K1 and K2.  It is mainly available in capsules but can also be found as a liquid in ‘emulsified’ form – this may be a good form for those who have impaired digestion of fats (e.g. due to gallbladder removal).