Cochrane Database Syst Rev
Can vitamin D keep young kids out of the doctor’s office for respiratory infections?
Clinical takeaway: Vitamin D supplementation appears safe and may slightly reduce the likelihood of ARI-related healthcare visits in children under five, but it does not meaningfully reduce episode frequency—so routine use solely for ARI prevention is not strongly supported.
Acute respiratory infections (ARIs) remain one of the leading causes of illness and healthcare use in young children worldwide, driving significant outpatient visits and hospitalizations.
A comprehensive Cochrane review analyzed 107 randomized trials involving 31,521 participants spanning pregnancy through early childhood.
Overall, vitamin D supplementation compared with placebo showed a modest reduction in the proportion of children requiring a doctor or hospital visit for an ARI. However, it “probably does not change how often each child visits a doctor or hospital” for these infections.
Dose comparisons offered little additional insight: higher-dose regimens (≥1000 IU/day) didn’t outperform lower doses in reducing ARI-related healthcare use, suggesting no clear dose-response advantage.
Safety signals were reassuring. Across trials, vitamin D had little to no effect on hypercalcemia risk, reinforcing its favorable safety profile in pediatric and perinatal populations.
The authors emphasized that while findings point to a potential small benefit, the certainty of evidence remains limited and heterogeneous across study designs, populations, and dosing strategies. As summarized in the review, vitamin D “may slightly reduce the number of young children who need a doctor or hospital visit” but doesn’t substantially alter overall ARI burden.
Taken together, these data suggest vitamin D is not a standalone solution for preventing respiratory infections in early childhood, though it may offer incremental benefit—particularly in populations at risk for deficiency.
Source: van Arragon M, et al. (2026, April 27). Cochrane Database Syst Rev. Vitamin D for preventing acute respiratory infections in children up to five years of age