WASHINGTON, July 18 (Xinhua) -- Giving young children high doses of vitamin D every day may not reduce of the risk of common cold in the winter, a new study suggested Tuesday.
In a clinical trial published in the U.S. journal JAMA, Jonathon Maguire, a pediatrician at St. Michael's Hospital, Canada, and colleagues randomly assigned 703 children aged one to five years old to receive 2,000 International Units per day (IU/d) of vitamin D oral supplementation or 400 IU/d for a minimum of four months between September and May.
On average, the 349 children who received the low dose, which is recommended by the American Academy of Pediatrics, had 1.91 colds per winter, while the 354 children who received the high dose had 1.97 colds, which Maguire said was of no statistical difference.
Colds and other viruses in the upper respiratory tract, including the nose and throat, are the most common infectious illnesses among children.
For the past 30 years, vitamin D has been thought to play a role in preventing or reducing these infections.
"We may have just busted a myth," said Maguire. "More is not always better. Our findings do not support the routine use of high dose vitamin D supplementation for the prevention of wintertime upper respiratory tract infections among healthy children."