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Vitamin D3 & K2 - occurrence and effect


Vitamins - in contrast to so-called vitaminoids - cannot be produced by our body, which is why they have to be constantly supplied from the outside. They ensure that the metabolism works properly, they strengthen the immune system and are indispensable for building cells, blood cells, bones and teeth. They also regulate the utilization of nutrients such as carbohydrates, proteins and minerals.

A distinction is made between fat and water soluble vitamins. Vitamins A, D, E and K are among the fat-soluble vitamins, whereas vitamins C and B, for example, are water-soluble. Therefore, vitamin D3 and K2 should always be taken in a fat solution.

Vitamin K

It owes its name to the fact that vitamin K is involved in blood clotting (= coagulation). With the K vitamins, a distinction is made between vitamin K1 (phylloquinone) and K2 (menaquinone). Vitamin K1 is mainly found in the leaves of green plants, where it is needed for photosynthesis (e.g. in spinach and broccoli). Vitamin K2, on the other hand, is formed by microorganisms and is therefore mainly found in fermented foods such as sauerkraut or some types of cheese. A certain amount of vitamin K2 is also formed in the human intestine. As a rule, only a very small part of the daily vitamin K2 requirement can be covered through food.

The fact that studies and proven positive effects for the organism are available to date, especially for vitamin K2 (it is known for K1 that it activates the coagulation factor prothrombin in the liver) is probably due to its significantly higher bioavailability and metabolism compared to vitamin K1. Only ~10% of the latter is absorbed through the intestinal mucosa – the rest is broken down in the liver. On the other hand, vitamin K2 is almost 100% absorbed because, unlike K11, it does not remain in the liver but passes from there into the bloodstream and into the tissue.

A possible undersupply of vitamin K2 can be attributed to a disturbed intestinal flora in addition to the diet - because part of the vitamin K2 is formed in the intestine. A disturbance of the intestinal flora can be traced back to certain diseases such as Crohn's disease or to the intake of antibiotics, antiepileptics or laxatives.

It should be noted that vitamin K2 exists in various variants, which differ in terms of the length of the chemical side arms (these are referred to as MK4 (menaquinone-4) to MK13 - MK4 and MK7 are the best known and best researched to date Variants) or differ in terms of their spatial structure (cis or trans variant). Cis isomers arise primarily when the K2 vitamin is produced synthetically and not obtained in a natural fermentation.

The most effective form of the K2 vitamins is menaquinone-7, also known as MK7, as it remains available in the blood for over 72 hours, while the majority of MK4 is available in the blood after just a few hours due to poorer binding hours is excreted. Since the body can only use the trans variant, it is imperative to pay attention to this declaration when comparing products. The higher the trans content, the better. With a trans share of more than 98%, the corresponding product can be called "all-trans".

Vitamin D3

Vitamin D3 needs sunlight to be able to be synthesized by the body. This applies to 80-90% of vitamin D3, because Germans only take in an average of 2.5 µg of vitamin D through food (e.g. fish, eggs or mushrooms).

Accordingly, a vitamin D3 deficiency results primarily from low exposure to sunlight; this is the case in our latitudes, especially in the months from October to March.But pregnancy, menopause or puberty can also contribute to a vitamin D3 deficiency due to hormonal changes. Finally, the body's ability to synthesize vitamin D3 decreases with age, so that a vitamin D3 deficiency is more common in seniors than in younger people is. This is particularly critical because cancer and many other chronic diseases occur more frequently in this phase of life. So it makes sense when naturopathy insists on going "out into the fresh air". Because there we fill up on solar energy even when the sky is overcast.

According to studies by the Robert Koch Institute from 2016, only 38.4% of adults in Germany have an adequate supply of vitamin D. (Source:

In the Journal of Health Monitoring 2016 1(2) of the Robert Koch Institute on pages 36 ff it says:

"An important function of vitamin D is its involvement in bone metabolism. Among other things, it promotes the absorption of calcium from the small intestine and hardens the bones. Severe and persistent vitamin D deficiency can lead, among other things, to softening of bones and deformities of the skeleton and thus to rickets in infancy and childhood and osteomalacia in adulthood. In old age, a vitamin D deficiency can also contribute to the development of osteoporosis. In recent years, observational studies have also found connections between low vitamin D levels and various chronic diseases such as type 2 diabetes mellitus, cardiovascular diseases or cancer [...] Due to the fact that only a few foods, such as Edible fish with a high fat content or mushrooms, which contain sufficient amounts of vitamin D, self-synthesis contributes the largest part to the supply with an estimated share of 80% to 90%. The radiation required for this occurs all year round only in regions below the 35th degree of latitude. At higher latitudes, the intensity and duration of adequate radiation decreases and vitamin D production becomes seasonal. This also applies to Germany, which lies between the 47th and 55th degree of latitude. […] There is an increased risk of vitamin D deficiency in older people and people who rarely spend time outdoors or only go outside with covered skin (e.g. due to a need for care or religious or cultural reasons) or who have dark skin . They also include people who have chronic gastrointestinal, liver or kidney diseases or who take medication that impairs vitamin D metabolism (e.g. antiepileptics or cytostatics)."

Just like vitamin K, vitamin D also occurs in different variants. The fact that vitamin D3 is used in dietary supplements is probably due to the fact that it increases the vitamin D level about twice as effectively as vitamin D2. This is probably due to the better absorption and longer retention of vitamin D3 in the bloodstream (source:

Benefit and mode of action

The following health claims are now permissible for vitamins K and D, provided that certain requirements, especially with regard toof the dosage are fulfilled:

  • Vitamin D contributes to the normal function of the immune system
  • Vitamin D has a role in cell division
  • Vitamin D contributes to the normal absorption/utilization of calcium and phosphorus
  • Vitamin D contributes to a normal calcium level in the blood
  • Vitamin D contributes to the maintenance of normal bones
  • Vitamin D helps maintain normal muscle function
  • Vitamin D contributes to the maintenance of normal teeth
  • Vitamin K contributes to normal blood clotting
  • Vitamin K contributes to the maintenance of normal bones

Vitamin K2 is required for activating the bone protein osteocalcin An increased level of non-activated osteocalcin leads to reduced bone density and thus to an increased risk of fracture. If there is a vitamin K2 deficiency, too little calcium is stored in the bones and osteoporosis can develop. Studies have shown that vitamin K2 can significantly reduce bone loss in osteoporosis patients (from a dose of 180 µg vitamin K2 per day). If vitamin D3 is administered at the same time, the two vitamins have a synergistic effect and bone density increases. On the other hand, osteoporosis must not be treated with high doses of vitamin D3 alone.

Vitamin K plays an important role in connection with calcium. Calcium is essential for stable bones and teeth; on the other hand, extremely undesirable in the form of deposits in the blood vessels with the risk of coronary diseases. And here vitamin K2 plays a crucial role by making calcium usable for the organism and activating certain proteins such as osteocalcin or the matrix GLA protein. Without vitamin K, these proteins remain ineffective and cannot do their job in the body. Osteocalcin regulates the mineralization of bones and teeth and ensures that calcium enters the bones. The matrix GLA protein ensures that calcium is not deposited in the blood vessels, but instead binds and transports it away.
This is exactly the mechanism by which K2 prevents osteoporosis and arteriosclerosis:

With a lack of vitamin D the bone building cells (osteoblasts) decrease and the bone volume shrinks. This can be corrected by taking vitamin D and more osteoblasts are formed again. However, vitamin D also promotes the maturation of bone-degrading cells (osteoclasts) and thus indirectly promotes bone degradation. This effect of vitamin D is suppressed by the simultaneous intake of vitamin K2. Furthermore, as described above, vitamin K2 is essential for the body's own production of osteocalcin, a protein that is involved in bone mineralization.

The so-called "Rotterdam Study" has shown that people who have consumed larger amounts of vitamin K2 over a period of 10 years have significantly less calcium deposits in the arteries and generally a significantly had better cardiovascular health than others.

Even earlier, sunbathing was used medically for people suffering from tuberculosis or people who had to work underground. It has been known since 1980 that sunlight has a positive effect even on serious illnesses: Cedric Garland, an epidemiologist at the University of California, showed in a study that many types of cancer were far less common in regions where the sun shone more often. International population studies later confirmed this connection.

Qidosha products

The QIDOSHA product combines the high-quality vitamins D3 & K2 in an ideal dosage in one preparation. It contains the MK7 / menaquinone-7) form of vitamin K2 that has the highest bioavailability, is more fat-soluble and stays in the blood for the longest time circulates. The trans proportion relevant for the effectiveness is greater than 98%, so that it is an "all-trans" product.

Unlike other dietary supplements, we chose oil as the dosage form for vitamins K2 and D3 because both K2 and D3 are fat-soluble vitamins and studies such as that by Traub et al. from the year 2014 with drops/oil as a dosage form suggest a higher absorption by the body than with tablets or capsules.

Since vitamins K2 and D3 are dependent on each other, their dosage should always be coordinated. Since K2 activates the proteins formed by vitamin D (see above), it is conceivable that a vitamin K2 deficiency can easily develop if the organism has a higher vitamin D supply, since more vitamin K is used for protein activation. Some studies have shown that a generally useful, high vitamin D level can even increase the risk of bone fractures if there is a vitamin K deficiency at the same time. That's why we don't offer any mono preparations with only one of the two vitamins each, but this combination preparation with a perfectly balanced combination of the two vitamins.


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