Thursday, October 4, 2012

Common Cold Prevention May Not Come from Taking Vitamin D



October 4, 2012

Looking for a quick and easy way to prevent the common cold in the upcoming winter season?  A recent study indicates that you may not be able to turn to a previous remedy of taking Vitamin D.

The average American adult will catch anywhere from 2 to 4 cold per year whereas a child can catch up to 10.  Past studies have shown that taking Vitamin D may provide a boost to your immune system.  Other studies have also shown that those with lower levels of Vitamin D are more susceptible to catching colds or other upper respiratory infections (URTIs).

The Vitamin D theory was recently done over an 18 month period in New Zealand.   In the study, a group of 322 healthy adults were instructed to take a either a Vitamin D supplement or a placebo.  Those who were in the vitamin supplement group were given 200,000 international units (IU) each month, or about 6,600 units a day for two months and 100,000 IU once a month or about 3,300 a day for the remainder of the study.  The recommendation by the Institute of Medicine of the National Academies located in Washington, DC is 600 IU of vitamin D daily and 800 IU daily for those over 70.

Participants in the study were instructed to tell the researchers when they felt like they were having upper respiratory symptoms.  At that time, a swab of their nose was taken to see if they have the cold virus.  At the end of the study, it was that there were 593 incidents of respiratory infections with an average of 3.7 colds per participants in the Vitamin D group.  In the placebo group there were 611 incidents of URTIs, with an average of 3.8 per person.  The average number of missed days of work was 12.  In terms of statistics, there was no noticeable difference between the two groups.

"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 URTIs. This result remained unchanged when the analysis included winter season or baseline [vitamin D] levels," the authors wrote.

Dr. Jeffrey Linder, an assistant professor at the Harvard Medical school and a practicing specialist in internal medicine at Brigham and Women’s Hospital in Boston stated that he believe Vitamin D should be added to the list of other cold remedies considered to be harmful or ineffective.  Others on the list include: Chinese herbs, asthma intranasal drugs, nasal irrigation, antiviral drugs, zinc, garlic, and Vitamin C.

In contrast, Ronald Eccles, the director of the Common Cold Center and a professor at Cardiff School of Bioscience at Cardiff University located in Wales, told BBD that this study does not necessarily prove that Vitamin D is not effective.  He stated that it does help to boost your immune system and he personally takes it every day.

"There is sufficient information to indicate that vitamin D is a vital vitamin for the immune system," he said.

The study was published in the October 2, 2012 issue of the Journal of American Medical Association.


Adapted from “Vitamin D may do nothing to prevent common colds” Michelle Castillo / CBS News / October 3, 2012