Vitamin D is important for health. Deficiency can be prevented. But be careful: an artificial oversupply can also be harmful.
Frankfurt – In the darker months of the year in particular, when the weather is cold and wet, only a few people drive outside. Working from home in times of the corona pandemic also means that fewer and fewer people are getting outdoors. This is particularly problematic for health. The human body needs sunlight, among other things, to produce an important vitamin: Vitamin D. It is extremely important for humans because it regulates the phosphate and calcium metabolism and therefore contributes to the hardening of the bones. Vitamin D also promotes a functioning immune system * and has an impact on muscle strength.
Vitamin D deficiency can therefore be bad for your health. As the Ärztezeitung summarizes, the list of diseases that are possibly related to the deficiency is getting longer and longer. It contains diseases such as susceptibility to infection, muscle weakness, heart attack, diabetes, rheumatism, depression, Alzheimer’s disease and multiple sclerosis. But when does a deficiency exist and what should be done about it?
Vitamin D: prevent deficiency without pills and Co.
According to the “German Nutrition Society” (DGE), there is a deficiency when the serum concentration of the marker 25-hydroxyvitamin-D is below 30 nanomoles per liter of serum. This type of deficiency is not the case with the majority of the population in Germany. However, almost 60 percent of Germans do not achieve the best possible blood concentration of 50 nanomoles per liter of serum, emphasizes the specialist society. As a consequence, this means that more than half of the potential of vitamin D for health is not fully exploited. However, according to experts, pills and dietary supplements are not necessarily recommended for healthy people. Because the formation of the vitamin can be promoted through an adapted lifestyle and targeted nutrition.
Sunlight on the skin can be enough for the body to produce the necessary amount of vitamin D. However, how much of this important vitamin is actually produced depends on factors such as the time of year, the weather, clothing and skin type. Therefore the tips of the DGE are to be understood only as orientation values. Between March and May, around ten to 25 minutes of sunbathing is enough in Germany, depending on skin type. About a quarter of the body surface should be exposed to sunlight, for example part of the arms and legs, as well as the hands and face. For skin types one and two, the skin type mentioned in the table refers to “light to very light skin color, light red or blond hair and blue or green eyes”. Skin type three is “medium skin color, dark hair and brown eyes”.
Vitamin D deficiency: in which foods the concentration is highest
However, these guide values only relate to the period between March and October. But what is the best way to behave in the dark season? Of course, it also helps to sit in the sun in winter, but since the angle of incidence of the sun’s rays is very flat, a significant production of the vitamin is not necessarily given, as the “Ärztezeitung” reports. The good thing about vitamin D is that it can be stored in the body. So if you build up a supply of the vitamin in summer, you can feed on it in the colder and less sunny months.
But the right diet can also help to drive up the vitamin D level. The concentration of this important vitamin is greatest in fatty fish such as herring and salmon. Eggs also have a notable concentration. Various mushrooms and liver are also recommended. However, the “Federal Institute for Risk Assessment” (BfR), for example, emphasizes that the intake of vitamin D through the diet only plays a subordinate role. The focus is still on the body’s own production from sunlight.
Overdose of Vitamin D? Too much of the vitamin can be harmful to health
There are not only pills and preparations with vitamin D, some foods are now fortified with vitamin D. However, taking such supplements is expressly only recommended if there is a proven vitamin D deficiency and an improvement in the level cannot be brought about by food or sun exposure, emphasizes the BfR. And there is a simple reason for that.
In addition to numerous studies, the Federal Institute for Risk Assessment has now also recognized the connection between a vitamin D deficiency and the risk of a severe course of Covid-19. *
Because an oversupply of vitamin D can have a negative impact on health. The “Federal Institute for Risk Assessment” warns: “With a regular daily intake of more than 100 micrograms of vitamin D, which is currently only possible through excessive intake of vitamin D preparations with normal eating habits, undesirable effects such as the formation of kidney stones or kidney calcification can occur . For medical reasons, however, higher amounts of vitamin D may be medically indicated. “
Vitamin D deficiency and risk groups: when experts recommend pills and co
However, some groups of people belong to the risk groups for a vitamin D deficiency. This includes, for example, people who, for health or other reasons, can only spend little time outdoors (e.g. due to illness). Also people who for cultural or religious reasons only leave the house with a body completely covered with clothing or people with dark skin color, according to the BfR. Elderly people also belong to the risk group, because the formation of vitamin D in the body decreases with age. In addition to older people, very young people also belong to the risk group. Because infants get only a very small supply of the vitamin through their breast milk and should be spared as far as possible from direct sunlight.