During the cold season, many families experience a common scenario: as soon as one infection is over, another is on the horizon. Coughing, runny noses, and sometimes fevers are par for the course. Respiratory infections rank among the most frequent reasons for doctor visits among children and can lead to missed workdays for parents and sleepless nights. Consequently, the desire for a simple protective measure—beyond hand washing and fresh air—becomes palpable.
This raises the question: could vitamin D supplements serve as a potential protective measure against respiratory infections? According to the Apotheken-Umschau, vitamin D is especially beneficial for strong bones, teeth, and muscle strength. Moreover, it contributes to a well-functioning immune system. Some studies suggest that low vitamin D levels may be linked to a higher risk of respiratory infections. A recent overview of studies aimed to explore whether vitamin D supplementation could effectively reduce the frequency or severity of these infections in children.
Why Are Respiratory Infections Particularly Dangerous for Children?
According to the Robert Koch Institute, acute respiratory infections (ARIs) encompass illnesses such as colds, COVID-19, and influenza. These are often triggered by various viruses that initially present similar symptoms but can lead to very different outcomes. In immunocompromised individuals and young children, such infections may lead to severe complications. According to the World Health Organization (WHO), ARIs are among the leading causes of death in children under five globally.
Children’s immune systems are still developing, which means they need to generate antibodies against easily transmitted pathogens. The Kindergesundheit.info portal notes that the lungs and airways of young children are smaller in size, making them more susceptible to viruses that attack these areas.
How Can Respiratory Infections Be Prevented?
To prevent respiratory infections, the AOK Health Magazine recommends several measures, including:
- Thorough hand washing,
- Sneezing into the elbow,
- Regular ventilation,
- Wearing masks,
- Receiving flu vaccinations, and
- Avoiding crowds.
Many of these measures are difficult to implement for young children, particularly those in group settings like daycare. So, can vitamin D intake serve as an alternative protective measure? A research team from New Zealand investigated this, analyzing 107 studies with over 31,500 participants.
Can Vitamin D Intake Protect Children from Respiratory Infections?
The findings of the overview by Marisa van Arragon and colleagues, published in the Cochrane Database of Systematic Reviews, in April 2026, suggested that a vitamin D deficiency in many children and pregnant women might make supplementation a straightforward preventative measure against acute respiratory infections in children under five. They argued that vitamin D supplementation is safe, cost-effective, and easy to administer.
The research explored whether vitamin D supplementation could reduce the number of children requiring treatment for acute respiratory infections and the average number of treatments per child. The studies examined the effects of vitamin D supplementation during pregnancy, infancy, and early childhood compared to control groups.
However, the results indicated that vitamin D has only a minor impact on the incidence of respiratory infections:
- The proportion of children visiting a doctor for a respiratory infection decreased slightly.
- The average number of doctor’s visits per child remained unchanged.
- Higher doses did not reduce the number of affected children or the number of doctors’ visits.
The authors of the review point out that the reliability of the studies reviewed is somewhat limited, as some included very few participants and used varying vitamin D dosages and methods of assessing acute respiratory infections. Thus, to reliably evaluate the effect of vitamin D on acute respiratory infections in young children, larger and methodologically sound studies are needed.
Do Children Need Additional Vitamin D?
According to the Apotheken-Umschau, children aged one year require approximately 20 micrograms of vitamin D daily. Approximately 80 to 90 percent of this daily requirement is produced in the skin under sunlight. Infants and toddlers, who may not be exposed to direct sunlight, can therefore suffer from low vitamin D levels, which may lead to rickets, a condition characterized by bone softening and deformities.
The German Society for Pediatrics and Adolescent Medicine (DGKJ) recommends a daily dose of 10–12.5 micrograms of vitamin D for children in the first twelve months of life. This prophylaxis can be continued during the winter months in the second year of life. A pediatrician can determine whether a vitamin D deficiency exists through a blood test.
However, self-supplementation of vitamin D in children without medical consultation is generally not recommended. According to a statement by the Federal Institute for Risk Assessment (BfR), significant clinical studies show no additional benefit from extra vitamin D supplementation for children with adequate levels. Moreover, excessively high doses may pose health risks. The BfR advises that high-dose preparations should be taken only under medical supervision. There have been reports of vitamin D toxicity due to excessive doses, sometimes resulting in severe outcomes like kidney damage.
