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Vitamin K1 and K2
Vitamin K1 and K2; coagulation and bone health.
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Vitamins, minerals and amino acids · Blood
Vitamin K2 MK-7
The form of vitamin K2 from fermented food and supplements; the value mainly follows intake.
At a glance
- Measured in blood
- In 1 test panel
- No special preparation
Explanation
Vitamin K2 MK-7: what is measured?
MK-7 (menaquinone-7) is a form of vitamin K2 with a long tail. It is made by bacteria, is found in fermented products such as natto and in some cheeses, and is the form most used in supplements. Because of that long tail, MK-7 stays in the blood much longer than the other forms, up to several days. Like the other forms of vitamin K, MK-7 helps activate clotting proteins and proteins in bone and the blood vessel wall.
What can it detect?
- The intake of vitamin K2 from fermented food or a supplement
- Low absorption of fat-soluble vitamins, for example with problems of the bile, pancreas or bowel
Result
What does the result mean?
Vitamin K2 MK-7 too high
A high value is almost always caused by an MK-7 supplement or by fermented food. There are no known symptoms or diseases that go with a high value. However, for anyone using a coumarin-type blood thinner, an MK-7 supplement does matter: because of its long duration of action, it disturbs the dose setting of those medicines for a long time.
Vitamin K2 MK-7 too low
A low or unmeasurable value is the normal result in the Netherlands in people who do not take a supplement, because the Dutch diet contains little MK-7. That does not mean there is too little vitamin K in the body: vitamin K1 from green vegetables and the menaquinones from the gut usually cover the need. With poor absorption of fats from the gut, the value can be truly low; the consequences of that are better read from the clotting test (PT or INR).
After an abnormal result
An abnormal value on its own usually does not lead to further testing. With a tendency to bleed, the GP looks at clotting (PT or INR) and at causes of poor fat absorption; with osteoporosis, the approach follows from the bone density scan and the risk of falling.
Reliability
How reliable is the test?
The body's vitamin K status cannot be read from a single blood value, and the meaning of an abnormal MK-7 value has been little studied. The value mainly reflects whether a supplement or fermented food has been used in the past few days. There are no agreed cut-off values. Whether extra vitamin K prevents fractures has not been sufficiently shown; the guideline on osteoporosis and fracture prevention therefore does not recommend vitamin K supplements, not even with a low blood value.
What can affect the result?
- An MK-7 supplement raises the value for days; without a supplement, the value in most Dutch people is low or unmeasurable.
- The result depends on the fat intake at the meal, because vitamin K is fat-soluble.
- Coumarin-type blood thinners (acenocoumarol, phenprocoumon) block the action of vitamin K and not the level; the result then says nothing about clotting, while MK-7 actually disturbs the dose setting for a long time.
- There are no standardized reference values; methods and limits differ per laboratory.
Who it is for
Who is the test useful for?
Useful for
The result says little in people without symptoms. With osteoporosis or an increased risk of fractures it adds little, because it has not been shown that extra vitamin K prevents fractures. At most, the test shows whether a supplement reaches the blood.
How common is it?
A confirmed vitamin K deficiency is rare in adults in the Netherlands. How often a low MK-7 value occurs is not known and has no established meaning for health.
Dutch medical specialists' guideline (FMS) on osteoporosis and fracture prevention and Netherlands Nutrition Centre (Voedingscentrum); no Dutch registration figure available
Drawbacks and risks
- A low result can cause unnecessary worry or lead to supplements whose benefit has not been shown.
- Anyone using a coumarin blood thinner who starts taking MK-7 on their own initiative disturbs the dose setting of those medicines for a long time.
Get tested
Vitamin K2 MK-7: test panels
Vitamin K2 MK-7 is part of these test panels. You order online and have your blood drawn at a collection point or collect the sample at home.
Evidence
Sources
This explanation is based on Dutch guidelines and independent information. It is general information, not a diagnosis. Discuss an abnormal result with your GP.
More about risks and resultsMore explanations
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