TORONTO – A new study suggests that taking large doses of vitamin D supplements don’t fend off a cold or reduce symptoms, despite previous reports that state the vitamin may be useful in fighting illness.
“The main finding from this study is that a monthly dose of 100,000 IU of vitamin D3 in healthy adults did not significantly reduce the incidence or severity of upper respiratory tract infections,” the authors wrote in the study, which is published in this month’s Journal of the American Medical Association. “This result remained unchanged when the analysis included winter season or baseline 25-OHD levels.”
Researchers in New Zealand studied 322 men and women from Christchurch, New Zealand and found that participants who received vitamin D pills were not less likely to have fewer or less colds than those who received a placebo.
While the vitamin D group received an average of 3.7 colds per person during the 18 month study period, the placebo group received an average of about 3.8 colds per person during the same time frame.
According to the study, subjects in both groups missed the same number of work days and their cold symptoms lasted about 12 days on average. Researchers, however, did conclude that “further research is required to clarify whether there is benefit from supplementation in other populations and with other dosing regimens.”
Get weekly health news
Vitamin D levels can vary widely in the population. Fair-skinned people in sunny regions tend to have the most while dark-skinned people who do not get much sun exposure tend to have the least.
Several studies over the years have questioned the role of vitamin D supplements in reducing or fighting the common cold. In 2008, a study published in the medical journal Archives of Internal Medicines found that people with the lowest levels of vitamin D in their blood were the most likely to catch colds.
Previous studies also highlight the other health benefits of the sunshine vitamin.
A report published in July in the New England Journal of Medicine found that older adults who took a daily dose of at about 800 international units (IU) reduced their risk of hip fractures by 30 per cent and other breaks by 14 per cent.
In 2011, a report from the Institute of Medicine recommended that most children and adults should get about 600 and 800 IU of vitamin D a day. It also concluded that the daily dosages were recommended exclusively for bone health and that a lack of evidence currently existed that suggested Vitamin D had other health benefits.
The Canadian Cancer Society recommends 1,000 international units (IU) a day in fall and winter for all adults, and year-round for those over 50 or with dark skin.
FULL REPORT: Effect of Vitamin D3 Supplementation on Upper Respiratory Tract Infections in Healthy Adults
– with files from The Canadian Press
Comments
Want to discuss? Please read our Commenting Policy first.