New Delhi: Zinc lozenges have shown promise in treating common cold by shortening its duration by 40 percent.
Interest in zinc lozenges was spurred by the example of a young girl in the early eighties who made her common cold go by dissolving a zinc tablet in her mouth instead of swallowing it.
Since then over a dozen studies have been carried out to find out whether zinc lozenges are effective, but the results of those studies have diverged.
Harri Hemila of the University of Helsinki, Finland, carried out a meta-analysis of all the placebo-controlled trials examining their effect on common cold infections, reports the Open Respiratory Medicine Journal.
Of the 13 trial comparisons identified, five used a total daily zinc dose of less than 75 mg and uniformly those five comparisons found no effect of zinc. Three trials used zinc acetate in daily doses of over 75 mg, with the average indicating a 42 percent reduction in the duration of colds.
Five trials used zinc salts other than acetate in daily doses of over 75 mg, with the average indicating a 20 percent decrease in the duration of colds, according to a Helsinki statement.
In several studies, zinc lozenges caused adverse effects, such as bad taste, but there is no evidence that zinc lozenges might cause long term harm.
Furthermore, in the most recent trial on zinc acetate lozenges, there were no significant differences between the zinc and placebo groups in the occurrence of adverse effects although the daily dose of zinc was 92 mg.
Hemila concluded that since a large proportion of trial participants have remained without adverse effects, zinc lozenges might be useful for them as a treatment option for the common cold.