A new study from the University of Otago, Christchurch, has ended speculation that vitamin D supplements may help prevent people from catching the common cold.
The research, published today in the Journal of the American Medical Association, was part of a large scale study of vitamin D (called the Vitamin D and Acute Respiratory Infection Study or VIDARIS). Researchers followed over 300 Cantabrians given monthly doses of either a placebo or a vitamin D supplement. After 18 months of monitoring, they found no significant differences between the groups in terms of incidence or severity of respiratory tract infections.
Several previous studies have hinted at a link between low vitamin D levels and upper respiratory tract infections (URTIs), but there has not been conclusive research into how supplements might affect infections – until now.
The researchers concluded that the high doses of vitamin D used in the study “did not reduce the incidence or severity of URTIs in healthy, predominantly European adults with near-normal vitamin D levels”. However the study noted that very few of the participants were vitamin D deficient, and that individuals lacking vitamin D may benefit more from supplements than those who had normal levels.
Lead researcher Dr David Murdoch said in an Otago media release, “VIDARIS is the first study to convincingly show that vitamin D does not prevent colds in healthy adults. However, it is important to note that very few people in our study had extremely low levels of vitamin D at the beginning. So, our findings may not apply to these people and to children who should now be the focus of further research.”
The research has been covered widely overseas. Examples include:
Huffington Post: Vitamin D No Help For Colds, Study Suggests
The Press: Vitamin D won’t keep the doctor away – study
The New Zealand Herald: Sunshine Will Not Help Prevent Common Colds