Vitamin D - Health and good mood through sun

vitamin d nutrients

What is vitamin D?

Vitamin D, also known as calciferol, is a fat-soluble vitamin that performs hormone-like functions and therefore strictly speaking is not a vitamin. Many people know it as the “sun vitamin” because it can be produced in the body by solar radiation and synthesis. It is formed from precursors that are already present in the body and therefore does not have to be supplied by food.

More about vitamins and other micronutrients can be found in our Nutrients section.

Why is vitamin D so important?

Vitamin D, especially vitamin D3, is involved in a large number of processes in the body. Here you can find the “most important” functions:

  • It promotes absorption, i.e. the absorption of calcium and phosphate through the intestines.
  • It is also responsible for the mineralisation of the bones. During mineralization, chemical elements are released and incorporated into inorganic substances, such as bones in this case. This ensures stable and healthy bones.
  • It also regulates the calcium and phosphate metabolism. These substances in turn ensure the stability and strength of the bones.
  • The vitamin D content in the body has an influence on muscle strength. A deficiency leads above all to a weakening of the grip strength and the calf and hip muscles.

Daily vitamin D requirement


The German Society for Nutrition recommends 20 micrograms of vitamin D per day. However, this value applies in the absence of the body’s own production. A 5-25 minute sunbathing break (depending on skin type and season) with a clear face, hands and a larger part of arms and legs is recommended. But ATTENTION: The recommendation should be taken with extreme caution:

Current recommondation Desired recommondation
20 micrograms per day = 800iE 125 – 175 micrograms per day = 5000-7000iE
Corresponds to 20-25 minutes of sun (depending on skin type and season) Equivalent to 2-4 hours of sun (depending on skin type and season)

Experts have been trying for years to increase the recommendations. The current recommended values, which are considered `normal`, actually indicate a severe deficiency. The reason for this is that the recommended Vitamin D values are based purely on bone health. However, many other illnesses also stem from a vitamin D deficiency. By the time a person reaches the level of vitamin D deficiency at which they are experiencing bone problems, they will already have a whole host of other problems. Experts internationally are therefore calling to increase the recommended Vitamin D levels from the current 800iE to 5000 – 7000iE. Many studies support this thesis. These increased values would suggest we spend a minimum of 2-4 hours in the sun, opposed to the current recommendation of 5-25 minutes. This makes absolute sense when looking at our genetics.

“We wouldn’t have to stay in the sun for 5-25 minutes, but rather 2-4 hours”

Which foods are a good source of vitamin D?

The body produces its own vitamin D rather than obtaining it from food. It synthesises vitamin D under the skin through sunlight. Fortification through food is therefore not generally required. This is different for every person and depends on different factors, such as the season or the latitude.

“Vitamin D intake through diet is less important.”

List: TOP Food with Vitamin D

As already mentioned, vitamin D is not supplied by food, but is produced by the body itself. There are very few foods in which it is naturally available in very small quantities:

Vitamin D deficiency

Vitamin D Mangel Symptome

Consequences of a vitamin D deficiency:

  • It leads to insufficient mineralization of the bones.
  • In childhood this can lead to rickets (bones are soft and can become deformed)
  • In adults, this is called osteomalacia
  • It also carries the risk of developing osteoporosis at an advanced age. As a result, falls in old age can lead to faster bone fractures.

What to do when the sun does not shine in winter?

In UK, the sun’s rays do not provide sufficient vitamin D during the winter months. But don’t worry! Your body has the ability to store enough up during the summer months (in fat, muscle tissue and the liver) to keep you going over the winter months. The prerequisite, of course, is that you get enough sun during the summer.

“By getting enough sunlight, you can store vitamin D for the winter”

What are supplements good for?

A supplement should only be taken as a last resort – if there is no improvement in the body’s own vitamin D synthesis through diet or sunlight. Vitamin D3 products in combination with vitamin K2 and a high-quality carrier substance such as vegetable oils are a sensible supplement. These are especially useful for people with an office job who are outdoors for less than an hour a day during the peak sunshine. Especially during the winter, a supplement is important for maintaining health and energy levels due to the fewer hours of sunshine.


If you eat a balanced and varied diet and regularly go out into the fresh air, you don’t have to worry about vitamin D deficiency. However, if you don’t get a lot of sunshine – whether from your office job or your home – you should pay particular attention to ensuring that your body can produce enough vitamin D or compensate for the deficit with supplements.

Frequently asked questions and answers

Vitamin D is mainly stored in our fat and muscle tissue, a small part also in the liver. If you had enough sunshine in the summer months, you will get through the winter well with the fairly large vitamin D storage.

Risk groups deficiency are all those people who take little or no outdoor exercise. This also includes people who cover themselves up for religious reasons so that the sun’s rays have no chance of reaching their skin. People with darker skin can produce less vitamin D and are therefore also included. As the synthesis of vitamin D decreases with age, older people are also a risk group, as are babies. They should not yet be exposed to direct sunlight, as their skin’s own protective mechanism is not yet fully developed. In addition, the vitamin D content of breast milk is so low that it cannot sufficiently fill the stores.

No. Solariums should generally be avoided. They increase the risk of skin cancer enormously especially during childhood and adolescence. So it´s much better to stay clear of them!


Deutsche Gesellschaft für Ernährung. (2020). Nährstoffzufuhr über Supplemente. In 12. Ernährungsbericht 2012 – Kapitel 1 – Ernährungssituation in Deutschland. Zugriff am 18.06.2020 unter

Deutsche Gesellschaft für Ernährung, (2020). Referenzwerte für die Nährstoffzufuhr. Zugriff am 18.06.2020 unter

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