How do you determine vitamin D deficiency

Vitamin D Deficiency - A Hype?


Again and again in Germany there is talk of vitamin D deficiency and undersupply. Usually you don't need pills!

Are you often tired? Do you work in closed rooms? Do you use sunscreen? Then you may be underserved. At least that's what a self-test on the website of a pharmaceutical company suggests. The nice thing is: The supposed deficiency can be remedied very easily - with the over-the-counter preparation that the company offers. It's about vitamin D.

One thing is certain: a real vitamin D deficiency is actually harmful to health. But that is not the case with most people in Germany.

Vitamin D is the preliminary stage of a vital hormone, explains Prof. Helmut Schatz from the board of the German Society for Endocrinology (DGE). It is particularly important for healthy bones, but it also influences the function of muscles. In contrast to other vitamins, humans only take in a small part of vitamin D through food - for example through fatty sea fish. The body produces 80 to 90 percent in the skin itself with the help of sunlight.

Germany is not exactly sun-drenched. More and more people therefore seem to believe that they are suffering from a vitamin D deficiency. Pharmacies alone sold vitamin D preparations for around 177 million euros in 2017. That's what IQVIA, a company that monitors the pharmaceutical market, has calculated.

But what exactly is a defect? "We only talk about it when people have symptoms, that is, when they are ill," explains Birgit Niemann from the Federal Institute for Risk Assessment (BfR). There used to be widespread deficiency symptoms, for example with iodine. The consumption of salt fortified with iodine has therefore been recommended across Germany since the 1980s. “That is not the case with vitamin D,” emphasizes Niemann. "We expressly do not share the view that there is a comprehensive vitamin D deficiency in Germany."

The BfR experts are not only interested in whether the population is lacking something - they also want to know how optimally people are being taken care of. “And there is still room for improvement with many vitamins,” says Niemann. Vitamin D is also one of them.

According to the Robert Koch Institute, a good half of adults in Germany do not achieve the serum concentration of 50 nanomoles per liter (nmol / L) or 20 nanograms per milliliter (ng / ml), which is regarded as optimal. Do they all have a defect? “No,” emphasizes Niemann. “But it could be that you have a risk of undersupply.” Because the risk of undersupply always exists when the serum concentration is below the optimum value. However, doctors only speak of a deficiency when the value is much lower - 10 ng / ml for a moderate deficiency and 5 ng / ml for a severe deficiency. Both are relatively rare, reports Schatz.

Babies, who are therefore given vitamin D everywhere, and a few others have a higher risk: For example, people who do not leave the house at all or only veiled, seniors over 65 years of age and people with dark skin. For these groups, prophylactic administration of vitamin D can be considered, explains Schatz.

But undersupply doesn't sound like something you'd like to have. But what does that actually mean in concrete terms? “That is at the core of the problem: we don't know,” explains Schatz. In numerous studies, scientists have tried to find out whether people with low vitamin D levels die earlier, whether they are more likely to develop cancer or have a heart attack.


A number of studies have also found a connection between respiratory and rheumatic diseases or diabetes and a low vitamin D concentration in the blood. “But the question here is: does the low vitamin D value increase the risk of rheumatism, for example? Or is it the other way around: Does the disease affect the vitamin D level? "

As long as there are no reliable findings, the German Society for Endocrinology, apart from the groups mentioned, usually sees no reason to swallow vitamin D capsules in healthy adults under 65 years of age. The option of drugs for erectile dysfunction is considered separately. “This is of course good business for the pharmaceutical companies. But we don't treat blood values, we treat people with symptoms, ”says Schatz. The crucial question for him and the specialist society: Do people actually get sick less often when they swallow vitamin D?

In addition to the DGE, the Stiftung Warentest also comes to the conclusion that this has not yet been clearly proven. In March 2018, the testers took a close look at the current study situation. You write: “According to current knowledge, taking vitamin D preparations cannot prevent cancer, diabetes or cardiovascular disease. Vitamin D pills are of no use to healthy, active adults. "

The Stiftung Warentest advises those who really want to know whether they are adequately supplied with a blood test via their family doctor. If he sees no reason for the check, the patient has to pay the 20 euros himself. The review is not part of a normal check-up.

Anyone who thinks that they cannot make ends meet without dietary supplements can swallow such pills at their own expense, added Schatz. Dosages of 800 to 1000 international units (IU) at least do not harm the body. If someone ingests more than 4000 IU for no medical reason, but their kidneys, for example, may suffer.

But then there is still the natural way to stock up on vitamin D: the sun. If you want to contribute to the optimal care of your body, you should go out the door every day. “You don't have to lie in the sun half the day for this,” explains Niemann. “25 minutes a day is enough.” Around a third of the body should be exposed to the sun. “As a rule of thumb, we say: half the time to sunburn,” added Schatz.

There is no need to worry that the skin does not produce enough vitamin D in winter. “Anyone who regularly spends a short time outside in the summer fills up their storage so that they can get through the winter safely.” Walks are also worthwhile in winter. Because even when the sky is overcast, vitamin D is still formed in the skin.

Source: dpa