Vitamin K2 is responsible for the smooth functioning of many of the body’s most important processes, including bone health, heart health and immunity. A deficiency in Vitamin K2 can be extremely dangerous but, unfortunately, the signs are often difficult to spot.

Vitamin K2 does some more obvious jobs, such as transporting calcium to bone and teeth, increasing their density and helping to prevent breakage, chips and fractures, but it also does the inconspicuous work of helping the blood to clot and of encouraging the decalcification of the body’s blood vessels and soft tissues which can become blocked with age or because of lifestyle factors such as smoking or poor diet.

What is a fat-soluble vitamin?

Vitamin K2 vital is a fat-soluble vitamin, meaning that it is best absorbed along with fats in the diet and can be stored in the body's fatty tissue. Compared to the other fat-soluble vitamins - vitamins A, D, and E - Vitamin K2 cannot be stored in the body for very prolonged periods of time. Therefore Vitamin K2 deficiency is a more common deficiency than any of the other fat-solubles, particularly if you don’t get a lot of it in your diet or are not taking a supplement.

A recent randomised study that looked at 452 healthy adults in the USA found that 438 of them - a staggering 97% - were either deficiency or insufficient in Vitamin K2.

As stated above, whilst Vitamin K2 might be a fat-soluble vitamin, the body is unable to keep hold of it for a prolonged period of time.

On the whole, we eat far less Vitamin K than we did 50 years ago. A large reason that deficiency is so common in North America and Europe is that the typical diet doesn’t contain a lot of the Vitamin K2-rich foods that our grandparents and great grandparents would have likely consumed. Foods like liver and other organ meats - historically important dietary sources of Vitamin K2 - are no longer fashionable, and as a rule we now prefer muscle meat to organ meat.

The increase in the number of people following a vegetarian and vegan diet in recent years has driven these foods further still from our plates.

Why are people in the US and in Europe more deficient in Vitamin K?

Foods such as sauerkraut, kimchi and natto (fermented soy beans) are also high in Vitamin K2. Vitamin K2 deficiency, therefore, is not nearly so common in Asian countries or cultures where fermentation is common and where fermented foods make up a large proportion of a typical diet.

Whilst in many cultures Vitamin K2 intake is still ample, the cultural change in the foods eaten in Europe and North America, compounded by less efficient storage of Vitamin K2 when compared with other fat-soluble vitamins, is a serious problem, with potentially devastating effects for our collective heart health, bone density and immune system.

Your skin is bleeding too much or bruising easily

Your body needs Vitamin K2 in order to produce the GLA proteins that help blood to clot. If you’re vitamin K deficient, your body doesn’t have enough of these proteins. Bleeding too much when you cut yourself, or bruising easily can be signs that your blood is not clotting efficiently, a leading cause of which is Vitamin K2 deficiency.

Other related symptoms are developing small blood clots beneath your finger and toe nails, and passing stools that appear dark - almost black - or that contains blood.

You have weak bones or teeth

Working together with Vitamin D3, Vitamin K2 is responsible for distributing calcium throughout the body and ensuring that the bones and tissues get an adequate supply. If bones and teeth don’t receive ample calcium they will become weak and you will be more susceptible to fractures, breakages and even osteoporosis.

Furthermore, Vitamin K2 not only transports calcium to bone, increasing bone density and helping to prevent and heal fractures, but it also helps to protect against calcium build-up, or calcification, of the body’s blood vessels and soft tissues. Without Vitamin K2 your body cannot break down these plaques and in extreme or prolonged cases this can result in heart attack or stroke.

You frequently become ill

Another note on calcium and its relationship to Vitamin K2. Calcium is a mineral that has been scientifically shown to play a key role in the activation of immunity cells in the body. There is only one way to effectively metabolise calcium and to ensure that it ends up reaching these cells: adequate intake of both Vitamin D3 and Vitamin K2. These two vitamins work together to promote calcium absorption and to maintain desirable levels of calcium in the blood.

When your blood calcium levels are low, your immunity is compromised. Therefore it stands to reason that one of the most commonly reported symptoms of Vitamin K2 deficiency (often, unsurprisingly, misdiagnosed) is frequent bouts of illness and a propensity to catch every cold and virus going. If this sounds like you, you should consider taking a supplement.

There are also a host of non-dietary factors that may contribute to or worsen K2 deficiency. These include:

• Current antibiotic use
• Long-term antibiotic use
• Following a low fat diet
• Fat malabsorption conditions
• Fat blocking pills (commonly marketed as weight-loss supplements)
• Some cholesterol-lowering drugs
• Dilantin use during pregnancy
• GI tract diseases
• Liver diseases
• Estrogen drugs, including HRT
• Anticoagulants and blood thinning medication

Children (particularly babies) and adults over 40 are most likely to be Vitamin K2 deficient, but as we saw above, deficiency or insufficiency affects approximately 97% of adults so almost all of us need to take a K2 supplement.

Unless you're eating animal fats, organ meats, and fermented foods on a regular basis - which, let’s face it, most of us are not - then you are exceedingly likely to be deficient or insufficient in Vitamin K2. Unless you are in the 3% of people who have enough Vitamin K2 in their blood, you’ll need to supplement.