Vitamin D supplements reduce risk of viral upper respiratory infections in children with lower concentrations.

Aim: Vitamin D is crucial for the immune system, as it enhances pathogen-fighting cells and reduces inflammation. We reviewed serum 25-hydroxyvitamin D (25(OH)D) concentrations in children with viral upper respiratory tract infections (URTIs) and the impact of vitamin D supplements on those infections.

Methods: A mini literature review was conducted from 1 January 2000 to 30 April 2024. It used PubMed, Google Scholar, Cochrane and Scopus and focused on children aged 0-18 years.

Results: The review comprised 12 studies: seven randomised controlled trials, two prospective studies, two case-control studies and one cross-sectional study. The findings included lower 25(OH)D concentrations in children more susceptible to URTIs and significantly lower levels in those with recurrent infections. One study found reduced 25(OH)D concentrations and immunoglobulin G levels in children with URTIs. Of the nine studies that examined vitamin D supplements, five reported benefits for children with URTIs, one only showed short-term effects and three found no significant reductions. Two reported that taking 2000 IU a day did not reduce URTIs any more than 400 IU and high-dose supplements may be unnecessary.

Conclusion: Children with viral URTIs often had lower vitamin D concentrations and supplements frequently helped to reduce the risk of these infections.