In order to provide your body with sufficient vitamins throughout the year, it can be particularly useful in some cases to use dietary supplements. Especially with vitamin D3 and K2, the use of supplements seems to make a lot of sense, as a large number of people can be shown to have a deficiency.
In order to compensate for this deficiency, it is important to choose the right dosage. In this article, we want to explain to you what you need to look out for when taking the right dosage of vitamin D3 and K2, what health benefits are associated with taking these vitamins and when these vitamins are particularly important.
the essentials in brief
- Vitamin D3 and K2 are fat-soluble vitamins that are essential for humans and help the body to stay healthy. A combined intake of the two vitamins is recommended, as they complement and regulate each other.
- In order to provide your body with sufficient vitamin D3 and K2 throughout the year, a healthy and balanced diet is often not enough, since vitamin D3 in particular is only contained in small amounts in food and is also primarily absorbed through direct sunlight can. The intake of vitamin D3 and K2 preparations is therefore particularly useful.
- Vitamin D3 and K2 preparations are available in different dosages and forms. The dosages always provide guidelines and can be roughly divided into three different forms of therapy. In order to provide your body with the right amount of vitamin D3 and K2, your own vitamin D level should be tested in advance.
Definition: What is vitamin D3 and vitamin K2?
In order to understand how vitamin D3 and K2 must be dosed and why the two vitamins are often taken in combination, it is important to define them individually at the beginning. In this way, the effect of the vitamins on the body is explained in detail. A brief description of the modes of action of the two vitamins follows.
What is vitamin D3 and why does the body need it?
Vitamin D3 is a fat-soluble vitamin and is also called cholecalciferol. Vitamin D3 is a form of vitamin D, which can be absorbed through the skin mainly through exposure to sunlight.
Through this process, the body converts the vitamin into calcitriol, the biologically active form of vitamin D. Vitamin D is therefore the only vitamin that the body can produce itself and is only ingested in small amounts through food. In this respect, vitamin D3 can also be regarded as a kind of hormone precursor. (1)
Vitamin D3 is essential to human life and has several health benefits.
For example, it promotes the formation and maturation of bone stem cells and is responsible for controlling calcium absorption. In addition, the vitamin strengthens the immune system, strengthens the muscles, protects nerve cells in the brain and has a positive effect on both the cardiovascular system and the human psyche. (2.3)
What is vitamin K2 and why does the body need it?
Vitamin K2 belongs together with vitamin K1 to the vitamin K group and is also a fat-soluble vitamin. While vitamin K1 can mainly be absorbed from plants but only survives in the human body for a short time, K2 can mainly be found in animal sources. In addition, vitamin K2 can also be formed by certain bacteria in the intestine, which means that it can remain in the body for up to 72 hours.
Vitamin K2 is also considered an essential vitamin.
The vitamin contributes, for example, to the maintenance of healthy bones and supports the development of strong and healthy teeth. In addition, vitamin K2 prevents calcium from being deposited in the arteries and reduces existing deposits. Vitamin K2 thus ensures healthy blood clotting. (4.5)
Background: What you should know about the dosage of vitamin D3 and K2
In order to be able to answer your question exactly how you should dose vitamin D3 and K2, you should take a closer look at the two vitamins at the beginning. For this reason, we want to explain to you at this point which foods contain the two vitamins, which dietary supplements are available and which factors influence the dosage of vitamin D3 and K2.
What are the advantages of a combined intake of vitamin D3 and K2?
Vitamin D3 supports the body in being able to absorb and properly control calcium. For example, vitamin D3 ensures that calcium is absorbed from food in the intestine.
Vitamin D3 and vitamin K2 complement and regulate each other.
Two proteins are required for this to succeed: osteocalcin and matrix-gla protein. These are synthesized through an adequate supply of vitamin D3, but remain in their inactive form. Only by absorbing vitamin K2 is the body able to convert these proteins into their active form.
This binds the necessary calcium and also deposits it where the body needs it. Vitamin D3 and vitamin K2 thus complement and regulate each other and thus ensure, for example, the healthy development of bone tissue. (6)
How can vitamin D3 and K2 be absorbed in principle?
Vitamins can usually only be absorbed through the food that is added to your body. However, as already described, vitamin D3 is the only vitamin that can be produced by the body itself by absorbing sunlight through the skin.
So in this section we want to give you an overview of different foods that contain both vitamin D3 and K2 and also explain how vitamin D3 can be absorbed through sunlight.
While vitamin K1 is mainly found in green leafy vegetables such as kale, collards or spinach, vitamin K2 is only found in animal foods. In the table below we give you an overview of foods with vitamin K2 content and also indicate how many micrograms per 100 grams are contained in the respective products.
|Groceries||Content of vitamin K2 µg/100g|
|Natto (fermented soybeans)||998|
As already mentioned, vitamin D3 is only found in very few foods because it can primarily be absorbed through the skin through exposure to the sun. Nevertheless, vitamin D3 is also contained in a few foods that have a very high fat content. The following table shows you the respective product and the vitamin D3 content.
|Groceries||Content of vitamin D3 µg/100g|
|cod liver oil||300|
At this point it is clear that vitamin D3 is found in some foods, but only in relative amounts. In order to be able to absorb enough vitamin D3 through food, it would therefore be necessary to eat large amounts of fish every day. In addition, with a vegetarian or vegan diet, only little or no vitamin D3 can be ingested through food. (7)
Vitamin D3 is therefore primarily absorbed through our skin through exposure to the sun. This is primarily a preliminary stage. Only in the body itself does the vitamin go through various chemical processes, whereby the vitamin can be converted into its bioactive hormone form (calcitriol).
Vitamin D3 is mainly absorbed through the skin through sunlight and from there converted in the body. (Image source: Zac Durant / unsplash.com)
In order to be able to absorb enough vitamin D3 from sunlight, people in countries like Germany, Austria or Switzerland have to be outdoors on a regular basis.
However, since most people spend most of their time indoors and cold seasons and few hours of sunshine make it difficult to spend time outside, it is not so easy to absorb enough vitamin D3 through the skin under these circumstances. Long clothing and sunscreen in the summer months also mean that vitamin D3 cannot be absorbed. (8th)
So that the body can be supplied with sufficient vitamin D3 throughout the year, it is almost inevitable nowadays to take food supplements.
In what form can vitamin D3 and K2 be taken as a dietary supplement?
If you decide to take vitamin D3 in combination with K2 as a dietary supplement, you basically have the option of choosing a remedy in the form of tablets, capsules or drops. At this point we would like to introduce you to the two types of dietary supplements in more detail and explain the different advantages and disadvantages.
A common form of vitamin D3 and K2 supplements are tablets. These can usually be purchased online, in pharmacies, but also in drugstores or health food stores. For vitamin D3 K2 preparations in tablet form, it is recommended to take 1 tablet per day with some liquid.
These can be chewed, sucked or simply swallowed and can be taken independently of meals. It is always important to ensure that the recommended amount of the preparations is not exceeded.
Vitamin D3 and K2 preparations can be taken in different forms. (Image source: Kayla Maurais / unsplash.com)
Vitamin D3 K2 preparations in tablet form often contain unnecessary additives that lead to the absorption of the vitamin being weakened. In order for the effect of the dietary supplements to unfold, it is recommended to take the preparations over a longer period of time.
Another way to absorb vitamin D3 and K2 is to take capsules. These are – just like tablets – available everywhere, but offer the advantage that they only rarely contain unnecessary additives and are therefore better suited for absorbing vitamin D3 and K2.
However, capsules have the disadvantage that they are slightly larger than ordinary tablets. Capsules are therefore unsuitable for people who usually find it difficult to swallow medication. In addition, capsules often contain gelatine, which is why they are also unsuitable for vegetarians or vegans.
Probably the best way to take vitamin D3 and K2 as a supplement is in the form of drops. This is because the vitamins are already dissolved in fat. Since the two vitamins are fat-soluble vitamins, they can be better absorbed in the form of oil drops. Furthermore, drops also have no other additives, which further improves absorption.
The disadvantage of drop preparations is often the right dosage. As a result of the drops, it can quickly happen that you take too much or too little of the vitamin preparations yourself. In addition, the preparations have a shorter shelf life, are relatively expensive compared to the other options and are usually only available online or in pharmacies.
How must vitamin D3 be dosed?
Official recommendations advise adults to take a daily amount of 400-800 IU (10-20 µg) depending on their age. This is to prevent a vitamin D deficiency from occurring in the human body.
At this point, however, it must also be mentioned that the correct dosage of vitamin D3 is currently still very controversial in science and the general recommended dose is now being regularly raised.
So that you can find the right dosage for you, it would be advisable to have your own vitamin D level checked in advance. This test can be carried out by the general practitioner, or you can carry it out yourself with a purchased test.
Basically, a distinction can be made between three different vitamin D3 therapies and supplements: (9)
- High-dose initial therapy: this form of therapy is primarily recommended for people who have had their vitamin D levels checked and who have been diagnosed with a vitamin D deficiency. The therapy thus aims to raise your own vitamin D level again in a very short time in order to compensate for the deficiency as quickly as possible.
- Maintenance therapy/supplement: In order to keep your vitamin D level constant throughout the year, it is recommended to take vitamin D supplements even when there is a deficiency. Depending on the season and spatial conditions, the dose can vary. So it is very important to get enough vitamin D3, especially in winter in northern regions, but also in summer, when you spend a lot of time indoors and therefore have little contact with the sun.
- High-dose long-term therapy for illness: Since vitamin D3 is important for the body in many ways and is involved in various health-promoting processes, it is important to take sufficient vitamin D3 in the form of food supplements, especially in the case of serious illnesses. This long-term therapy is therefore particularly recommended for autoimmune diseases. The doctor treating you will give you the exact dose.
For those people who do not know their exact vitamin D level, we have provided the following table. This provides a reference value for the various dosage recommendations and is based on scientific publications and findings on the therapy of vitamin D deficiency. (9.10)
|initial therapy||fast compensation of a vitamin D deficiency||1 × 50,000 IU, then 10,000 IU per day for 4 weeks|
|Maintenance therapy/supplement in winter||Maintaining good vitamin D levels||3000-5000 IU|
|Maintenance therapy/supplement in summer||Maintaining good vitamin D levels||400-2000 IU|
At this point we would like to mention again that these recommendations are guide values. If you suspect a vitamin D deficiency, it is always advisable to have your own vitamin D level checked. This is the only way to accurately calculate the right dosage for each individual.
How must vitamin K2 be dosed in combination with D3?
Since vitamin D3 can be absorbed particularly well in combination with vitamin K2, we now want to add another column to the table set up earlier. In this way we can give you an approximate guideline for each of the individual forms of therapy.
|therapy||Goal||Vitamin D3||Vitamin K2|
|initial therapy||fast compensation of a vitamin D deficiency||1 × 50,000 IU, then 10,000 IU per day for 4 weeks||200 mcg/day|
|Maintenance therapy/supplement in winter||Maintaining good vitamin D levels||3000-5000 IU||150-200 µg/day|
|Maintenance therapy/supplement in summer||Maintaining good vitamin D levels||400-2000 IU||150-200 µg/day|
If you decide on a vitamin D3 and K2 preparation, make sure above all that the two values of the vitamins are coordinated. This is the only way to ensure that the absorption of the vitamins is ideally promoted and well absorbed by the body.
For whom is vitamin D3 and K2 suitable?
In principle, taking vitamin D3 and K2 preparations is suitable for everyone and, due to the difficulty in absorbing vitamin D3 naturally, is also recommended in many ways to avoid deficiency symptoms.
- Adults: Adults or full-grown individuals are advised to follow the approximate guidelines previously presented in the two tables above. With increasing age, higher dosages can be beneficial in maintaining a healthy immune system and thus protecting against diseases associated with aging.(11)
- Babies and toddlers: even at a very young age, it is often recommended to take vitamin D3 and K3 supplements, since vitamin D3 can only be stored in the body for longer with increasing age. Infants and young children are therefore particularly at risk and often suffer from vitamin D deficiency. In order to strengthen your child's immune system and prevent the development of numerous chronic diseases, you should make sure that your child is supplied with sufficient vitamin D3 and K2. (12)
- Pets: Just like for us humans, vitamin D3 and K2 are extremely important for animals. Vitamin D is essential for growing dogs and cats in particular and is required for bone formation. However, pets have an excellent store of vitamin D, which is why it rarely has to be added to food. In animals, vitamin K is usually synthesized in the gut by bacteria. Nevertheless, vitamin K should also be ingested through food to prevent deficiency. (13)
Is an overdose of vitamin D3 and K2 dangerous?
A vitamin D3 overdose leads to a severely excessive calcium intake. In this case one speaks of hypercalcaemia. However, numerous studies now confirm that an overdose can only occur with an extremely high dose of vitamin D3 over a longer period of time and is therefore relatively unlikely.
Vitamin D3 is only dangerous at a dose of 300,000 IU or a regular intake of 40,000 IU per day.
Vitamin D3 is therefore only dangerous at a dose of 300,000 IU or a regular intake of 40,000 IU per day. Studies have confirmed that no health problems have been identified when taking 10,000 IU per day.
Vitamin K2 is a natural vitamin and free from all side effects. Those proteins that are responsible for blood clotting have only a limited absorption capacity.
Accordingly, no excess of vitamin K2 can be absorbed and there is no risk of blood thickening. Excessive intake of vitamin K2 through diet is also harmless for adults.
Learn more about vitamin K2 overdose .
In newborns, however, an excess of vitamin K can be dangerous and lead to the breakdown of red blood cells. Special caution is therefore required here.
What happens if you overdose on vitamin D3 and K2?
An overdose of vitamin D can cause poisoning in the body. This is caused by excessive absorption of calcium in the intestines and can lead to vomiting, thirst, urination, tiredness and constipation. However, an overdose of vitamin D is extremely unlikely and can only occur with long-term overconsumption of 40,000 IU per day. (14)
The possibly increased vitamin K2/magnesium consumption should be compensated by a correspondingly increased intake of these nutrients.
What effects does a vitamin D3 and K2 deficiency have on the body?
A vitamin D3 and K2 deficiency is much more serious than an overdose. Since the two vitamins ensure a healthy body in so many areas, it is extremely important to ensure that vitamin D3 and K2 levels are always maintained.
A lack of vitamin D3 and K2 can therefore have different effects on the body and lead to different symptoms (15).
Mild symptoms as a result of a vitamin D3 deficiency would be, for example:
- negative mood
- mood swings
- sleep problems
- weak limbs
- lack of concentration
However, with a long-term lack of vitamin D3, stronger symptoms develop, such as:
- bone diseases
- immune disorders
Just like a vitamin D3 deficiency, a vitamin K2 deficiency also has serious consequences for physical health. The lack of vitamin K2 can therefore lead to the following diseases:
- joint inflammation
- insulin resistance
How should vitamin D3 and K2 be dosed in conjunction with other vitamins?
The extent to which vitamin D3 and K2 complement each other has been underlined several times in this article. But the combination with other vitamins also contributes to a particularly good absorption of vitamin D3 and K2 and thus promotes your own health. Therefore, there follows a brief description of other vitamins that you should take together with vitamin D3 and K2.
Magnesium is essential for vitamin D3 to be converted. Magnesium thus helps convert vitamin D3 into its active form. If there is a magnesium deficiency, vitamin D3 can only be absorbed with difficulty. Vitamin D3 is therefore linked to the magnesium supply. (16)
An amount of 400 mg per day is sufficient to cover the need for magnesium. A large amount of magnesium is suitable, for example, in broccoli, wholemeal bread, brown rice, legumes, nuts or potatoes. A balanced diet ensures that your magnesium level is covered and the intake of vitamin D3 can be secured.
As you have already learned, vitamin D3 is responsible for calcium getting into the intestines. Vitamin K2 supports this absorption. However, in order for sufficient calcium to reach the intestines, it is important that this has been supplied in advance with sufficient amounts of food.
Chinese cabbage, kale, broccoli, beans, almonds, dried figs and various dairy products are important sources of calcium, which is why these foods should be on your menu regularly.
In order to ensure a sufficient supply of vitamin D3 and K2, it is advisable to also ensure that you consume enough calcium. Accordingly, around 1000 mg of calcium should be consumed per day to cover the requirement. (17)
In order to keep body and mind healthy in the long term, an adequate intake of vitamins is absolutely necessary. Vitamin D3 in particular is an essential vitamin and supports the body in various processes.
Due to the small amounts in which vitamin D3 is contained in food and the difficulty in absorbing sufficient vitamin D3 from the sun, taking vitamin D3 preparations is often unavoidable. So that the intake via these dietary supplements can take place without any problems, a combined preparation of vitamin D3 and K2 should definitely be used.
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- Zittermann, A., von Helden, R., Grant, W., Kipshoven, C., & Ringe, JD (2009). An estimate of the survival benefit of improving vitamin D status in the adult German population. Dermato-endocrinology, 1(6), 300-306. https://doi.org/10.4161/derm.1.6.10970
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- Ambożewicz, E., Muszyńska, M., Tokajuk, G., Gęgotek, A., Jastrząb, A., & Skrzydlewska, E. (2018). Effect of vitamin D3 and K on metabolism of osteoblasts cultured with biomaterials. Free Radical Biology and Medicine, 120, S129.
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