The common cold is an irritation we can all do without. No cure has been found so far to alleviate its impact, but it seems that zinc tablets can perhaps cut its duration. A study found 70 per cent of people who took the tablets felt better by the fifth day, compared to just 27 per cent who did not. While previous research on zinc’s effectiveness has been mixed, this time the patients were given much higher doses in the form of zinc acetate tablets.
Dr Hari Hemila and colleagues from the University of Helsinki, studied data from three trials involving around 200 people. ‘The three-fold increase in the rate of recovery from the common cold is a clinically important effect,’ Dr Hemila said. ‘Given the evidence of efficacy, common cold patients may be instructed to try zinc acetate lozenges within 24 hours of onset of symptoms. However more work was needed on the most effective formulation and how often it should be taken.’
Most colds are caused by a type of bug called rhinovirus, which thrives and multiplies in the nasal passages and throat. Zinc may work by preventing the rhinovirus from multiplying and stop it lodging in mucous membranes in the respiratory system. The effect was not altered by allergies, smoking or the cold’s severity, researchers found. As the results were similar across age, sex and ethnic groups, the swifter recovery rate was applicable to all.
The dose was between 80 to 92 mg a day – much higher than the recommended 11mg for men and 8mg of women. However, none of the patients showed any side effects and zinc has safely been administered in much higher doses for other conditions. But Dr Hemila warned most lozenges in shops do not come in high enough doses to treat a cold. He said: ‘Given the strong evidence of efficacy and the low risk of adverse effects, common cold patients may already be encouraged to try zinc acetate lozenges not exceeding 100mg of elemental zinc per day for treating their colds.’
The latest findings confirm previous studies by Dr Hemila’s team, as well as those by Cardiff University’s Common Cold Centre. The NHS says there is some evidence taking zinc within 24 hours of the symptoms starting may shorten a cold but long-term care is not recommended as it could cause side effects such as nausea and a bad taste in the mouth. NHS experts say more research is needed to find out the best dose.
I believe caution is always recommended when on ongoing-research has not reached the stages when it could confidently advise its patients that the risk undertaken is minimal and the benefits are overwhelmingly encouraging.