What is vitamin D and what can it do?

Vitamin D: That’s this nutrient that we absorb through the sun? Especially in winter, however, this is not quite so easy.

The question quickly arises as to whether you should therefore also take tablets or other products. We’ll come back to that later.

In principle,
vitamin D
helps you with the following functions and areas :

• Vitamin D helps you with bone stability.
• Vitamin D is necessary for your teeth.
• Vitamin D is important for your immune system.
• Vitamin D can protect against acute respiratory infections.

Some will probably pay attention here: respiratory infections? Does this also help with SARS-CoV2 – or “Corona” for short? The fact is: Those who suffer from a vitamin D deficiency are more susceptible to infections – with Corona this is not so safe, as an American study from May 2021 shows.

If the supply is right, there is no evidence that a vitamin D intake brings anything beyond that. This is confirmed by the Federal Institute for Risk Assessment (BfR), the Robert Koch Institute (RKI) and the German Society for Nutrition (DGE).

On the contrary, if you take too much vitamin D, it can lead to serious health problems.

But now everything in order. Let’s start quite seriously: What is known for sure about vitamin D and not a classic advertising statement that should only lead to the purchase of a product.

Vitamin D can do that. The proven effect and when you need it

Right at the beginning you can anticipate that a visit to the doctor of trust is important. If your vitamin D level in the blood is too low, it makes sense to take it.

If a supplement contains at least 0.75 μg per daily dose (also applies to 0.75 μg per 100 g or 100 ml), one can speak of the following effects . Vitamin D helps to

• a normal utilization of calcium and phosphorus.
• a normal calcium level in the blood.
• normal bones and the preservation of these.
• normal muscle function.
• normal teeth.
• a normally functioning immune system – even in children.
• a lower risk of falling in old age, as vitamin D (at 20 μg per day) helps against the postural (postural instability) and muscle-related causes.

In addition, it is also useful in cell division . Children also benefit from an appropriate vitamin D supply, as healthy growth and equally healthy bone development is not possible without vitamin D.

However, there are also some legends about vitamin D. It has not been proven that a dose of vitamin D that goes beyond basic care has a preventive effect against cancer, diabetes, cardiovascular disease or nerve diseases. Science does not know this at the moment.

Likewise, muscle function is often exaggerated – it is not the fitness miracle cure. As recently as August 2021, a study by Diana Grove-Laugesen and Lars Rejnmark showed that more vitamin D than usual has no positive effect on muscle health or muscle strength.

We have now explained to you what vitamin D can do. Let’s take a step back and see why it can do that. Or in short:

So what is vitamin D?

As is so often the case with vitamins, vitamin D is not just a vitamin, but a whole group of fat-soluble vitamins. You will also have stumbled across vitamin D3 , which is also called cholecalciferol. It is the most important representative for our body.

Likewise, you probably know that it can be formed by solar radiation – or the UV-B radiation. This is almost true, because “only” the precursor 7-dehydrocholesterol is formed here, which is then converted into vitamin D3.

As with other nutrients, the term “vitamin” is not quite correct. Vitamins should actually be essential: This usually means that the body can produce enough of itself. In principle, however, this already works here with the help of solar radiation for many people.

If you don’t like fish, unfortunately you don’t have too much choice, because vitamin D occurs naturally, especially in fatty fish . Otherwise , dietary supplements are a common substitute prescribed by doctors. Especially the winter months rarely offer enough sun and through the clothing even less skin can absorb the radiation. In some, particularly dark countries, foods that are enriched with vitamin D are therefore increasingly used.

However, the height of the position of the sun is important, because if the angle of incidence of the sun’s rays is too low, nothing arrives at the body. As a result, north of Cologne, Erfurt and Dresden (51st parallel), no vitamin D3 is formed in the skin even at noon, e.B. in winter. South of San Francisco, the Algarve, southern Sicily and Antalya, however, this is possible all year round.

Vitamin D is significantly involved in calcium metabolism. This also means that it regulates the calcium level in the blood and helps to build bone. A vitamin D deficiency leads to diseases such as rickets (in children) or osteomalacia (in adults). The bones lose strength and become softer. It is not yet entirely certain whether the more well-known osteoporosis can also be a consequence of too little vitamin D in the blood.

The nutrient is processed in the liver and released into the blood. But let’s go further with the basics:

What you should pay attention to when taking vitamin D

The DGE generally recommends that you try to get enough vitamin D through the sun and your diet. If the supply is not guaranteed after verification by a blood test with the doctor, they recommend vitamin D preparations in the usual dosage (20μg per day). After a blood test, you know here how acute the deficiency actually is. However, the blood test is usually a chargeable individual health service.

Especially older people who live in nursing homes often get too little sun or absorb vitamin D poorly, which is why general supplementation is recommended there. These are among the risk groups. This also includes:

• People older than 65 years. However, women in particular are on average less well cared for than men for reasons that have not yet been clarified.
  • They are also affected because they are more often restricted in mobility
• People who usually want to go out in the sun with their skin covered or can’t.
• People who have a darker skin color because they are less able to absorb the UV-B rays.

According to the BfR, the usual dose of 20 μg per day does not mean that higher-dose vitamin D preparations, which are taken less frequently, are harmful. Studies to date show that health restrictions are unlikely with occasional consumption of higher doses (50-100 μg ). However, with long-term use, it is a health risk to consume too much vitamin D.

However, one should avoid dosages from 4,000 international units (equivalent to 100 μg per day), as these can lead to major side effects up to problems with the kidney.

Vitamin D: sun, fish and dietary supplements

In conclusion, vitamin D is one of the “vitamins” that you urgently need for our bones, our immune system and many other things .

We can all take on the sun in limited quantities, but especially north of the latitude, which goes through Cologne, Erfurt and Dresden, this is very difficult in the darker seasons. This is where fatty fish help.

If none of this is for you, a blood test may well show if you are suffering from a deficiency. After all, according to the study on the health of adults in Germany (2008-2011), about 15% of the population suffers from a vitamin D deficiency.

In this case, dietary supplements can reliably help and ensure a healthy vitamin D level with conscious dosage.