#Vitamin #Deficiency #Supplements #Prevent #Symptoms #NDR.de #Guide
As of: March 4, 2024 9:03 a.m
Because almost everyone has a vitamin D deficiency in the winter months, experts recommend additional vitamin D intake. Otherwise there is a risk of symptoms such as decreasing bone stability and immune deficiency.
Of course, it depends on the extent of the vitamin D deficiency – but experts agree: In winter it makes sense to take it as a dietary supplement. The recommended maximum amounts should under no circumstances be exceeded.
Vitamin D: Important for bones, metabolism and immune system
Vitamin D is essential for bone health: only with sufficient levels can calcium be absorbed in the intestine, which is needed for bone development. If there is a lack of vitamin D, calcium is not stored in the bones, but is released from the bone substance in order to keep the calcium level in the blood constant. If this happens over a long period of time, bone density decreases. The substance is also involved in many important metabolic processes in the body and is partly responsible for a functioning immune system.
Symptoms: Decreasing bone stability and immune deficiency
For people who, according to the Robert Koch Institute, do not have an “sufficient” supply of vitamin D, the deficiency is small and there are no health problems. However, a severe and long-term deficiency can have serious consequences:
- Weak bones: A mineralization disorder of the bone caused by severe vitamin D deficiency can lead to the bone being less stable and resilient and to bone fractures and delayed healing. Doctors assume that with sufficient vitamin D supply, up to 25,000 hip and femoral neck fractures could be prevented every year.
- Weakened immune system: There are vitamin D receptors in almost all organs and tissues of the body, so this hormone influences metabolism in many places. Scientists were able to prove that sufficient vitamin D also protects against respiratory infections. Experts assume that vitamin D has a decisive influence on the function and activity of certain immune cells: The substance appears to be responsible for activating T lymphocytes and stimulating them to divide. After contact with a pathogen, they produce vitamin D recognition proteins on the cell surface. Contact with the vitamin then leads to a strong increase in T lymphocytes, which help to defend the body against pathogens.
Absorption of vitamin D through sun and food
The body produces most of it through UVB rays from the sun. In addition, vitamin D can be absorbed through certain foods – for example by eating fatty fish, dairy products or eggs. But even with a very healthy and balanced diet, you can only cover 10 to 20 percent of your daily needs through food.
Causes: Vitamin D deficiency due to insufficient sun exposure
Until the age of industrialization, people were usually outside all the time in the summer months. As a result, their vitamin D stores were filled to maximum capacity in the fall and they got through the winter well. Nowadays, many people work indoors even in summer and to protect against skin cancer, they use sun creams with high sun protection factors and avoid direct sun.
The vitamin D absorbed in this way is usually enough for a sufficient vitamin D supply in the summer months. However, the vitamin D stores are not optimally filled and a deficiency occurs by winter at the latest.
At what values does one speak of a deficiency?
The vitamin D level in blood serum is given either in nanomoles per liter or in nanograms per milliliter. Serum values of less than 30 nmol/l (less than 12 ng/ml) mean a deficient vitamin D supply with an increased risk of diseases such as osteomalacia and osteoporosis. Experts consider serum values of 30 to less than 50 nmol/l (12 to less than 20 ng/ml) to be suboptimal care with possible consequences for bone health. Experts describe values above 50 nmol/l (12 to less than 20 ng/ml) as an adequate vitamin D level.
Taking vitamin D: Useful in winter
Because so many people do not have enough vitamin D, experts recommend taking additional vitamin D in the winter months. A prior determination of the vitamin D level is not absolutely necessary for most people.
The German Society for Nutrition recommends 800 international units (IU) daily – but many experts find slightly higher amounts to be sensible. Overall, however, the daily intake of vitamin D should not exceed 4,000 IU. The European Food Safety Authority (EFSA) calls this value the maximum upper limit. Important: This upper limit is the maximum recommended total daily intake – so it also includes the vitamin D that you get from sunlight and diet (additional vitamins are often added to many foods, so this should also be taken into account). Vitamin D as a dietary supplement can be taken in the form of tablets or drops.
Determining the vitamin D level through a blood test can be medically useful for chronically ill people or for certain symptoms. However, vitamin D tests are only of limited significance due to fluctuating results, but they do provide a rough guide.
Taking too much vitamin D is dangerous
In general, too much vitamin D is harmful. Because unlike some water-soluble vitamin C, the body cannot simply excrete excess vitamin D, but rather stores it. As a result, too high a vitamin D intake can lead to an acute or gradual overdose. The result can be calcification in organs – for example in the kidneys in the form of kidney stones. Only in rare cases and with certain diseases can an extreme vitamin D deficiency occur. Then it may make sense to take higher doses of vitamin D for a short time and only with medical advice. Then, for example, higher-dose preparations with 10,000 or 20,000 IU are prescribed to be taken weekly.
Medications can influence vitamin D production
Certain medications such as cortisone, diuretics, sleeping pills and anti-epileptic drugs can impair (in some cases even increase) the effect of vitamin D. Anyone who takes medication on a long-term basis should therefore definitely discuss the use of vitamin D preparations with their doctor.
Anyone who is prone to the formation of calcium-containing kidney stones, suffers from kidney weakness, sarcoidosis or parathyroid disease should also discuss taking vitamin D with their doctor. During pregnancy, vitamin D supplements should only be taken if there is a proven deficiency and under control of the calcium level, as an increased calcium concentration in the blood can harm the child in the womb.
Risk groups who often suffer from vitamin D deficiency
There are people who are particularly at risk of developing a severe vitamin D deficiency. Those affected should consume appropriate amounts in consultation with a doctor. This includes:
- People of all ages who barely get out because they sit indoors at a desk all day, for example. Chronically ill people and those in need of care who spend little time outdoors are also at risk.
- Dark-skinned people, as the higher melanin content of their skin provides greater protection against UVB radiation
- People who, for cultural or religious reasons, only go outdoors with their bodies completely covered
- Smoker
- High-performance athletes because they consume more vitamin D
- People who are very overweight – vitamin D accumulates in fatty tissue
- People who suffer from chronic gastrointestinal, liver or kidney diseases or who take medications such as anti-epileptics or cytostatics that impair vitamin D metabolism
Experts on the topic
Specialist in orthopedics, trauma surgery, sports medicine
Senior physician at the Institute for Osteology and Biomechanics
Center for Experimental Medicine
Lottestraße 59
22529 Hamburg
Head of the experimental and clinical osteology working group
Medical Director MVZ Endokrinologikum Göttingen
Department of Gastroenterology, Gastrointestinal Oncology and Endocrinology
Robert-Koch-Str. 40
37075 Göttingen
Nutritionist
Institute of Nutritional Medicine
Head of AG Pharmakonutrition
Ratzeburger Allee 160
23538 Lübeck
Further information
Dietary supplements can lead to an overdose of vitamins and minerals – with dangerous consequences. more
Studies of vitamin levels in the blood are often expensive. Specific tests for vitamin D or B12 are usually more useful. more
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Visit | 03/05/2024 | 8:15 p.m
