What is Vitamin K2? Health benefits and value of the supplement


Evening Standard

Insider's contributing wellness editor Sarah Ann Macklin on why this under-the-radar vitamin is so essential


We hear a lot about Vitamin K, but recently there’s been a lot of fuss over vitamin K2. But why is this the case and what is the difference between the two?

As a nutritionist, I try to make sure all my clients gain as many nutrients from their meals as opposed to supplements. Supplements are meant to help support a diet not replace an entire food group.

We still don’t know if supplements are as bioavailable to the body as they say they are, and there are so many different types. Many synthetic supplements may react differently in the body compared to eating real food, because you’re not eating a single nutrient, but a whole range of vitamins and minerals within that food which work together as cofactors.

Whole foods aren’t filled with bulking agents, like most synthetic supplements today. This isn’t to say supplements can't be helpful in certain situations when someone is on a restrictive diet and has a high risk of nutrient deficiency, but many people think a quick solution to healthy lifestyle is popping a pill, which sadly is not the case.

Vitamin K is a fat-soluble vitamin, essential to produce certain proteins which promotes blood clotting and regulates calcium homeostasis for bone regulation. Fat soluble vitamins are vitamins which are stored in the body, as opposed to water soluble vitamins which flush through our system and come out when we pee if not needed. Hence why, when you drink Berocca you may have luminous wee from water soluble vitamins which aren’t need. Therefore, you need to be careful when supplementing with vitamins which are fat soluble which are A, E, D and K. They can easily become toxic if consumed in high amounts.

What is the difference between Vitamin K and Vitamin K2?

Vitamin K1 contributes to bone health and blood clotting and it is stored in the body. Vitamin K2 is involved in blood coagulation and is a prime communicator, taking calcium out of the blood and into the bone matrix, in something called 'bone remodelling'. This is a process which helps renew our skeleton and prevent holey bones.


Extraordinarily, our entire skeleton is renewed every 7-10 years. Vitamin K2 also prevents calcium from accumulating in the walls of blood vessels - so it's particularly key if you're taking calcium supplements. 

How much vitamin K1 and K2 do we need?

Vitamin K1 deficiency is quite rare in adults as it is abundant in animal products and veggies such as spinach, broccoli and asparagus.

Vitamin K2 is a little more complicated. It has different side chains and lengths such K2-MK4, found in some meats, egg yolks and cheese, and K2-MK7 found in meat and natto (an ancient Japanese food of fermented soya beans) which is the only vegetarian source.


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Claire Thorburn