Vitamin D: Energy from the sun

Vitamin D plays an important role in bone and tooth development. Find out how it is made and how to get enough of it in this health tip.
Vitamins have countless important functions in our bodies and are essential for us humans. Unlike plants, though, we can’t produce them ourselves. We need to get them from food. Vitamin D is a slight exception: a precursor for cholesterol, which is found in the skin, is converted into vitamin D with the help of UVB rays from sunlight. Because the body is involved in the production of vitamin D, it is not strictly speaking a vitamin, but a hormone.

What does vitamin D do in our bodies?

The most important function of vitamin D in the body is its involvement in calcium absorption in the intestine. Calcium is a mineral that is needed for the formation of bones and teeth, so it’s an extremely important substance. Vitamin D helps to absorb calcium from food (for example from dairy products) in the intestine and store it in the bones. If the body doesn’t have enough vitamin D, not enough calcium will be absorbed and there is a risk of damage to the bones. Children with severe calcium deficiency can develop rickets, a disease where the bone tissue is too soft and the bones become bent as a result. In older people, osteoporosis can occur, where bones become less stable and more brittle.

Go and get some fresh air every day

80-90% of the vitamin D required on a daily basis is produced through the action of sunlight on the skin. So this means the key to getting enough vitamin D is to go outside every day and expose your skin to the sun. People who are particularly sensitive to UV rays can produce the necessary vitamin D in just 10 minutes, while people with less sensitive skin need 20-40 minutes. But always remember to apply sunscreen first and to avoid the blazing midday sun. Go out in the morning or afternoon instead.

The situation is a bit different in the winter. You tend to go outside less, most of your skin is covered up with clothing and the sun's rays are also much weaker than in the summer. It is estimated that 60% of the Swiss population have vitamin D deficiency in the winter. So it's worth giving it a bit of a boost by eating the right foods. Good foods are:

  • oily fish like wild salmon or herring
  • egg yolks
  • certain edible mushrooms like button mushrooms or chanterelles
  • dairy products

You can also take vitamin D drops. The Federal Office of Public Health recommends that children up to the age of one, people over 60, pregnant women and chronically ill people take vitamin D supplements all year round after consulting a doctor.

More isn’t always better

Vitamin D is a fat-soluble vitamin so it can be stored in fat and muscle tissue. If too much vitamin D is ingested, only a small amount can be excreted in the urine, unlike with water-soluble vitamins. This means you should not take vitamin D supplements if you spend enough time in sunlight, eat a balanced diet and are not diagnosed with a deficiency. Too much vitamin D can even be harmful because large amounts of calcium enter the bloodstream, which can lead to vomiting and muscle weakness, and in severe cases can even result in kidney damage or cardiac arrhythmia.

In the event of further health-related questions, SWICA customers can contact the santé24 telemedicine service free of charge on +41 44 404 86 86. A telemedicine practice licence allows santé24 physicians to provide additional medical services in cases that are suited to a telemedicine approach. SWICA customers can also use the BENECURA medical app to carry out a digital SymptomCheck and receive recommendations about what to do next. During a subsequent phone call with santé24, customers can decide for themselves whether to release their information from SymptomCheck to santé24.