Could High Doses of Vitamin D Protect Kids from Common Cold in Winter?

Winter time is when cases of upper respiratory tract infections in children one to five years of age are on the rise. The cold weather can be hard to handle if proper care is not taken. It is also the time when vitamin D levels are found to be low, which is said to be one of the possible factors for common cold and ill health. Earlier observational and clinical trial data have suggested a link between low levels of Vitamin D and increased rates of respiratory tract infections. But a new study done by University of Toronto found a different view during their research on the health of Canadian children and the impact of early health in later life. The findings revealed that giving high doses of Vitamin D to your child will not protect them from catching common cold in winters.

Vitamin D sources include sunlight and foods like eggs, tuna, seeds, etc. During winter, our vitamin D levels tend to lessen due to less sunlight. This is also the time when there's a rise in the number of common cold cases. The study compared the effect of high- and standard-dose of vitamin D on the risk of children catching a cold or flu in winter.

The researchers randomly assigned 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 results of the average number of infections for high-dose and the standard-dose groups respectively were 1.05 and 1.03 respectively.

"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," stated the study.

The study doesn't challenge the usefulness of the recommended vitamin D dosage, but suggests that high dosage may not be better for colds. A limitation of the study could be that children may have had upper respiratory tract infections without swabs being submitted.

The study was published in the Journal of the American Medical Association (JAMA)