04 May Study Compares Zinc Lozenges Used to Treat the Common Cold
MedicalResearch.com Interview with:
Harri Hemilä, MD, PhD
Department of Public Health
University of Helsinki
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Some zinc lozenges intended for treating the common cold have contained zinc acetate and some others have contained zinc gluconate. There have been proposals that zinc acetate might be more optimal salt for lozenges than zinc gluconate.
Therefore I compared the randomized trials that have used zinc acetate with zinc gluconate to see if there is difference between the lozenges. Although the average effect in 3 studies with zinc acetate lozenges was greater (40%) than the average effect in 4 studies with zinc gluconate lozenges (28%), that difference was explained by random variation.
I also analyzed the dose dependency of the effect and found that 2 studies that used 192 and 207 mg per day elemental zinc did not find greater benefit than 5 studies that used 80 to 92 mg per day zinc. The overall average effect of zinc lozenges was 33% reduction in common cold duration and that effect seems to be reached with doses less than 100 mg per day.
MedicalResearch.com: What should readers take away from your report?
Response: With properly formulated zinc lozenges it is possible to shorten the duration of colds by over 30%. However, the majority of zinc lozenges in the market may have either too low doses of zinc or they contain substances such as citric acid that bind zinc. Therefore, the findings of this study are not directly applicable to the wide variety of formulations of zinc lozenges on the market.
Some of the studies included common cold participants only if their colds had not lasted over 24 hours and it seems possible that the effects are greatest if the treatment is started soon after the onset of symptoms. Some patient have not liked the taste of zinc lozenges but in such a case the patient can simply stop taking them.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: The optimal composition of zinc lozenges should be investigated in addition to the optimum frequency of their administration. The possible effects of zinc lozenges on common cold complications such as sinusitis, otitis, and exacerbations of asthma should be examined.
MedicalResearch.com: Is there anything else you would like to add?
Response: There a popular saying that “there is no cure for the common cold”. That is false because of the strong evidence indicating that zinc lozenges can shorten common cold duration by over 30%. It is even possible that the wide spread belief has hampered the objective assessment of the evidence for the efficacy of zinc lozenges.
I dont have any conflicts of interest about zinc treatments or common cold treatments in general.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
Harri Hemil. Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM Open, 2017; 8 (5): 205427041769429 DOI: 10.1177/2054270417694291
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