Scientists on either side of the globe fail to agree on effectiveness of vitamin D supplements as a method to combat the common cold.

Children are four times more likely than adults to catch colds but researchers from New Zealand found "no convincing evidence" to show that taking vitamin D will fend off a cold after conducting the 'gold standard' of tests, a randomised placebo-controlled trial.

However, Prof Ronald Eccles, of the Common Cold Centre at Cardiff University, insists supplements can give the immune system a much-needed boost.

"There is sufficient information to indicate that vitamin D is a vital vitamin for the immune system," he said.  "Supplementation might help to support the immune system over the winter when we are short of vitamin D."

He did go on to concede that "supplements don't work for everyone" and the New Zealand research tends to suggest this with a greater percentage of the 161 people who took daily vitamin D for 18 months catching colds as the 161 who took placebos (fake pills).

While supplements increased blood levels of the vitamin in those involved in the study, reported in the Journal of the American Medical Association, this had no significant impact on their rate or severity of colds.

The vitamin D group caught an average 3.7 colds per person compared with 3.8 colds per person for the placebo group.

There was also no significant difference between the two groups in the number of days missed off work or school as a result of cold symptoms.

Posted 03/10/2012 by richard.hook@pavpub.com