Who are food supplements useful for? –

Vitamin D: dietary supplements are not necessary for most people

However, in the summer, it is important to replenish vitamin D reserves so that you do not have to worry about a deficiency during the dark months. The formation of vitamin D by the body in the skin takes place thanks to sunlight (UVB rays). In addition, the important vitamin is contained in many foods. Do you also need food supplements to build up reserves?

As the Federal Office for Consumer Protection and Food Safety (BVL) explains, the human body can store vitamin D, which was formed during the summer months, so that a supply sufficient is usually also provided during the winter months. However, not everyone can replenish their vitamin D stores in the summer and may need dietary supplements. The Federal Center for Nutrition (BZfE) explains who this concerns in a current message.

Dietary supplements are in fashion

Food supplements have been a trend for some time: as the Consumer Monitor 2021 (BfR; PDF) of the Federal Institute for Risk Assessment (BfR) shows, a third of the population takes vitamins from food supplements at least once a week, and every sixth person even daily.

45% of respondents said they consumed vitamin D via such preparations. According to BfR President Prof. Andreas Hensel, dietary supplements are not necessary for most people.

“Anyone who takes large doses of vitamins without it being necessary risks an oversupply and therefore adverse health effects,” explains the expert.

Participation in bone metabolism

The best-known function of vitamin D is its involvement in bone metabolism. It promotes the absorption of calcium from the gastrointestinal tract and hardens the bones. It influences muscle strength, regulates calcium and phosphate metabolism and is also involved in other metabolic processes in the body, explains the BfR on its website.

Vitamin D deficiency can have a huge impact on bone health. The most serious consequences are decalcification and ultimately bone softening (osteomalacia and osteoporosis).

Vitamin D requirements are only met to a small extent by food

According to the German Nutrition Society (DGE), the daily requirement for all age groups is 20 micrograms (1 microgram [µg] = 0.001 milligram [mg]) estimated, for infants (under 12 months) it is 10 µg. Another unit used for vitamin D is the "international unit" (IU). 1 µg corresponds to 40 IU or 1 IU corresponds to 0.025 µg.

However, the estimated requirement values ​​apply only in the absence of self-synthesis; because - and this is a really special position of this vitamin - it can be ingested through food or formed by man himself through exposure to UVB light (sunlight).

According to the BVL, however, only 10-20% of daily vitamin D requirements are met through food. Foods high in vitamin D are primarily fish and fish products (especially high-fat varieties such as herring, wild salmon, and sardines). Liver, egg yolk, and some edible mushrooms also contain smaller amounts of vitamin D.

In addition, some products such as margarines and spreads are fortified with vitamins, as the BZfE explains on its website.

Staying in the sun for a few minutes is enough

According to a coordinated recommendation of scientific institutions, professional societies and professional associations, staying in the sun for five to 25 minutes during the hot season is sufficient for sufficient synthesis of vitamin D if about one quarter of the body surface (face, hands and body parts) arms and legs) are uncovered.

A rule of thumb says: if our shadow outside is shorter than we are tall, we produce enough vitamin D. This is the case in our latitudes between April and October. The good thing: Like other fat-soluble vitamins, the human body stores the vitamin, primarily in fat and muscle tissue, but also in smaller amounts in the liver.

The storage capacity is relatively large overall, so that a sufficient supply is usually ensured even in the winter months.

Clarifying vitamin D supplementation with a doctor

For whom is vitamin D supplementation useful? The first to be mentioned here are infants; They are a risk group for vitamin D deficiency, explains the Healthy into Life network of the Federal Agency for Agriculture and Nutrition (BLE) on its website.

On the one hand, this is due to the fact that the vitamin D content of breast milk is very low (an average of 0.073 mcg per 100 milliliters) and, on the other hand, infants should not be exposed to direct light. from the sun; especially since the protective mechanism of the skin has yet to develop.

Undersupply risk groups also include people who (can) barely or not spend time outdoors. In addition, the elderly because the body's production of vitamin D decreases considerably with age and there are on average more people with reduced mobility, chronic illnesses and people in need of care in the population old.

Dietary supplements should always be taken in consultation with a doctor, although it is advisable to have your vitamin D status checked before taking any supplements.

Finally, the BZfE recalls that an overdose of vitamin D and the associated adverse effects are only possible through excessive oral intake (permanently more than 100 µg = 4,000 IU per day), but not through excessive exposure of the skin. under the sun. (ad)

Author and source information

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This text corresponds to the specifications of the specialized medical literature, medical guidelines and current studies and has been verified by health professionals.


Federal Food Centre: Replenishing vitamin D stores in summer, (accessed: August 17, 2022), Federal Food Center Federal Office for Consumer Protection and Food Safety: When is a vitamin D preparation still a food supplement?, (accessed on: August 17, 2022), Federal Office for Consumer Protection and Food Safety Federal Institute for Risk Assessment: Consumer Monitor 2021 (PDF), (accessed on: August 17, 2022) , Federal Institute for Risk AssessmentFederal Institute for Risk Assessment: Selected Questions and Answers on Vitamin D, (Accessed: August 17, 2022), Federal Institute for Risk AssessmentGerman Nutrition Society: Selected Questions and Answers on Vitamin D, (Accessed: August 17, 2022), German Nutrition SocietyFederal Nutrition Center: Vitamin D in Foods, (Accessed: August 17, 2022), Federal Food CenterOffice f Federal Agriculture and Food: Why Do Infants Need Vitamin D Too?, (Accessed: August 17, 2022), healthy into life

Important note:
This article contains general advice only and should not be used for self-diagnosis or treatment. It cannot substitute a visit to the doctor.