Why vitamin D is so important for children

As soon as the days get shorter and the fog prevents the weakening rays of sunshine from getting through, the sniffles begin. At the same time, more and more mums and dads are wondering whether vitamin D is really as important as health professionals say – and whether one drop of a vitamin D supplement a day is really enough to strengthen the immune system. The answer is clear: yes, but there are a few important points you should be aware of.

What does vitamin D do in the body?

Vitamin D is more than just a vitamin: it acts like a hormone and influences many processes in the body. It is particularly well known for its role in bone metabolism. It helps the body absorb calcium from food and incorporate it into the bones. Without enough vitamin D, the body is less able to utilise calcium, which weakens bone structure in the long term.

The immune system also benefits: vitamin D supports the body's defence against pathogens and helps ward off infections. Studies show that children with good vitamin D levels are less likely to suffer from respiratory diseases.

A prolonged lack of vitamin D can lead to a deficiency. In children, this can manifest itself in the form of rickets. This is a disorder in bone growth that can lead to soft, deformed bones. Today, rickets is rare in Switzerland, but a latent deficiency is widespread – especially in the winter months.

Who should be particularly careful

However, some children are at increased risk of deficiency not only in winter, but throughout the year. These include children with dark skin, because their skin is less efficient at producing vitamin D from sunlight. Children who spend a lot of time indoors or hardly ever play outside in winter also receive too little UVB radiation for their own production.

In addition, overweight children often have lower vitamin D levels. This is because the fat-soluble vitamin is stored in fat cells, meaning that less of it circulates in the blood. It is therefore particularly important to ensure an adequate supply during the growth phase.

How much vitamin D is good for children?

The Swiss Society for Nutrition (SGE) provides clear recommendations on vitamin D intake. For infants up to one year old, the recommended daily dose is 400 IU (international units – a measure of the biological activity of a vitamin. 600 IU of vitamin D corresponds to approximately 15 micrograms). This amount is usually covered by standardised vitamin D drops, which are administered daily from birth.

In Switzerland, between October and March, there is often not enough sunlight to produce sufficient vitamin D.

From their first birthday onwards, the requirement increases to 600 IU per day. This corresponds to approximately one drop of a standard preparation. Most children do not reach this amount through food alone. Even with regular outdoor exposure, the requirement can hardly be met during the winter months because the sun's intensity is too low.

The only way to determine whether a child is receiving adequate nutrition is through a blood test. However, this is only recommended if there is specific suspicion of a deficiency. In most cases, it is sufficient to follow the general recommendations for supplementation.

How children absorb vitamin D

Most vitamin D is produced in the skin – through exposure to sunlight. However, in Switzerland, there is often not enough sunlight between October and March to produce sufficient vitamin D. People who spend a lot of time indoors or always use sunscreen also produce less vitamin D.

In addition, vitamin D is found in a few foods – such as fatty fish like salmon or sardines, eggs, liver or fortified products like margarine or plant-based milk. However, very few children are particularly enthusiastic about these foods. But that's not a problem, because even a balanced diet usually only provides a small portion of the daily requirement.

For this reason, supplementation is recommended as standard for infants in Switzerland. For older children, the following applies: those who spend little time outdoors, rarely eat oily fish and see little sun in winter often benefit from additional supplementation. It is best to consult your paediatrician.