How important is vitamin D for our health? This is the subject of heated debate among doctors. Some swear by vitamin D cures, others consider this an unnecessary trend. How is the vitamin D supply in Germany?
Vitamin D is the only vitamin that the body can make itself. The so-called endogenous synthesis takes place in the skin. Vitamin D acts like a hormone in the body and plays an important role in numerous metabolic processes. The “sun vitamin” is of central importance, for example, in the absorption of calcium and bone health. However, the synthesis only works if sufficient UVB radiation is absorbed through the skin. According to experts, it is sufficient to spend around 15 minutes a day in sunlight and to shine it on the face and back of the hand. You play it safe if you spend a few minutes in the sun regularly in winter. In summer, you usually automatically get enough sun rays. However, there are exceptions (see below).
Nevertheless, many have a vitamin D value that is too low
This is because the body’s production of vitamin D does not work equally well for everyone. Some manage to compensate for the insufficient body’s own vitamin D synthesis through many stays in the sun. It doesn’t work with others.
According to studies by the German Nutrition Society (DGE), around a third of the population is undersupplied with vitamin D. Those affected have a blood serum concentration of less than 30 nmol / l 25-hydroxyvitamin-D – according to the DGE, they are considered to be inadequate. And just under 40 percent of Germans are only adequately supplied with vitamin D.
But vitamin supplements are not the solution
Overview studies on the effectiveness of artificially added vitamin D are sobering. The manufacturers’ promises that taking vitamin D can prevent or alleviate cardiovascular diseases and cancer and prevent osteoporosis have not been proven in a large number of studies. It is particularly sobering to discover that the meta-analyzes found almost no effect on bone health among those who took vitamin D via pills or capsules. According to current knowledge, taking vitamin D does not protect against osteoporosis, heart attacks, strokes or cancer.
It is believed that the widespread lack of vitamin D can also indicate poor health. Scientists suspect that low vitamin D levels are not the cause of chronic diseases, but that, conversely, aging processes and inflammatory processes lower the vitamin D levels.
In old age, the body loses the ability to synthesize vitamin D
Given these numbers, vitamin D cures are in vogue. But due to the data situation, most doctors and nutritionists are skeptical about the preventive use of high-dose vitamin D supplements. They advise you to go outdoors regularly so that the body can replenish its stores for the winter – especially after the winter. “Let the sun be well dosed on your skin,” recommends Isabelle C. Keller of the German Nutrition Society. Because over 80 percent of the vitamin D requirement is covered by solar radiation. No extensive sunbathing is necessary for this, the endogenous synthesis works even when the sky is overcast.
In the months between April and October, depending on your skin type, around 20 minutes outdoors are sufficient. However, at least parts of the body should be uncovered and free of sunscreen – but only for this relatively short period to avoid sunburn. The remaining 10 to 20 percent of vitamin D needs can be met through food, with oily fish such as mackerel or herring containing most of the nutrient.
Vitamin D test is not a cash benefit
So if you regularly stay outdoors, you don’t normally need to swallow any additional vitamin D supplements, says Keller. “We only recommend that certain risk groups who do not spend enough time outdoors go to the doctor and have their vitamin D levels determined.” In addition to infants who are additionally provided with vitamin D in the first year of life, the risk group includes above all the elderly and infirm, as well as people who, for other reasons, do little or nothing outdoors or have very dark skin. As a rule, insured persons must pay for the test, which costs around 30 euros, out of their own pocket.
The ability to synthesize vitamin D is lost in old age
“In old age, the ability to synthesize vitamin D through the skin decreases,” emphasizes Keller. Therefore, an additional vitamin D dose of at least 800 international units (IU) may make sense in people over 65. However, Keller warns against shearing all the seniors together: “Take the sprightly pensioner who works a lot in the garden or goes out regularly with the dog, he does not need a supplement.” It is different with sick, frail people.
Can artificial vitamin D harm?
The rule ‘a lot helps a lot’ does not apply to vitamins. At least not if you take them in the form of tablets. The effects of synthetic synthetic vitamins can still be determined through long-term studies. The tenor among nutritionists for all vitamins is that they should not be taken lightly in artificial form, because they can also harm. So you should only take vitamins, no matter what, in the form of tablets or powder if the doctor expressly recommends it. Overdosing vitamin D with food is not possible.
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