A study published in The Royal Society of Medicine Journals found that zinc gluconate lozenges may be as effective as zinc acetate lozenges for treating the common cold.
Zinc lozenges appear to benefit common cold outcomes through the release of free zinc ions into the oropharyngeal region, however the salt used in lozenges may impact the ability of zinc to be released. Dr. Harri Hemila from the University of Helsinki, Finland, aimed to compare zinc acetate vs. zinc gluconate lozenges in their efficacy to treat the common cold and to asses the extent of the dose-dependent effect. Dr. Hemila performed a meta-analysis on placebo-controlled zinc lozenge trials with the daily dose >75mg. An inverse-variance random-effects method was used to measure the pooled effect of zinc lozenges on the duration of the cold.
A total of seven trials enrolling 575 patients with naturally acquired common colds was included for the analysis.
The analysis revealed that the average common cold duration was 33% (95% CI: 21-45%) shorter for the zinc groups across all the trials. Specifically, three trials that used zinc acetate lozenges showed that the common cold was shortened by 40% and four trials that used zinc gluconate showed it was shortened by 28%. The difference between the two salt formulations was not significant (12%, 95% CI: –12 to +36).
Trials where zinc doses ranged from 80–92mg daily demonstrated a reduction in the common cold by 33%. This effect was increased to 35% in trials where zinc doses ranged from 192–207mg daily. The difference between high vs. low doses of zinc was not significant (2%, 95% CI: –29 to +32) indicating that doses over 100mg/day do not appear to exert additional benefits.
Generally, the findings suggest that lozenges composed of zinc gluconate are as effective as zinc acetate. More research is needed to identify the ideal lozenge composition and dosage, however, “the current evidence of efficacy for zinc lozenges is so strong that common cold patients should be encouraged to try them for treating their colds, but the patients should ascertain that the lozenges do not contain citric acid or its salt citrate,” concluded Dr. Hemila.
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