A Canadian study set out to find whether supplementing with high-dose vitamin D helped prevent children catching colds… and found it didn’t
Previous studies have suggested that children may be more likely to catch colds if they have low levels of serum 25-hydroxyvitamin D.
Canadian researchers set out to find out whether daily high-dose administration of vitamin D reduced overall wintertime upper respiratory tract infections.
The study, published in JAMA, saw Dr Jonathon L. Maguire of the University of Toronto, and colleagues randomly assign children aged one through five years to receive 2,000 IU/d of vitamin D oral supplementation (high-dose group; n=349) or 400 IU/d (standard-dose group; n=354) for a minimum of four months between September and May.
The average number of laboratory-confirmed (based on parent-collected nasal swabs) upper respiratory tract infections per child were 1.05 for the high-dose group and 1.03 for the standard-dose group.
There was also no significant difference in the median time to the first laboratory-confirmed infection: 3.95 months for the high-dose group vs 3.29 months for the standard-dose group, or number of parent-reported upper respiratory tract illnesses between groups (625 for high-dose vs 600 for standard-dose groups).
“These findings do not support the routine use of high-dose vitamin D supplementation in children for the prevention of viral upper respiratory tract infections,” the authors write.
A limitation of the study was that children may have had upper respiratory tract infections without swabs being submitted.