Taking zinc lozenges not exceeding 100 mg of elemental zinc per day may make recovery from common cold faster, suggests new research.The dose of zinc may help common cold patients within 24 hours of the onset of symptoms.Analysing three randomised controlled trials, the researchers found that zinc acetate lozenges may increase the rate of recovery from common cold three fold.

On the fifth day, 70 per cent of the zinc lozenge patients had recovered compared with 27 per cent of the placebo patients, showed the study published in the journal Open Forum Infectious Disease.The dose of zinc in the three studies was between 80 to 92 mg/day.Such doses are substantially higher than the recommended daily zinc intake in the US, which is 11 mg/day for men and 8 mg/day for women.

However, in certain other controlled studies, unrelated to the common cold, zinc has been administered in doses of 100 to 150 mg/day to patients for months with few adverse effects.The researchers believe that it seems highly unlikely that 80-92 mg/day of zinc for one to two weeks, starting very soon after the onset of the first cold symptoms, might lead to long-term adverse effects.None of the three analysed zinc lozenge studies observed serious adverse effects of zinc.

“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 100 mg of elemental zinc per day for treating their colds,” said lead author Harri Hemila from the University of Helsinki, Finland.