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- Published on: 18 May 2018
- Published on: 19 March 2018
- Published on: 18 May 2018Zinc lozenges and vitamin C for high-performance athletes
In their International Olympic Committee consensus statement, Maughan et al. reviewed the evidence for dietary supplements for high-performance athletes [1].
They wrote in regard to zinc that “Cochrane review shows benefit of [using] zinc acetate lozenges (75 mg) to decrease duration of URS [upper respiratory symptoms]” [1, Table 4]. This statement was based on their reading of the Cochrane review (2013) by Singh and Das [2], which was withdrawn in 2015 because of plagiarism [3]. In addition, the same Cochrane review had a large number of other severe problems [4]. In the above statement, Maughan et al. imply that only zinc acetate lozenges are effective; however, a recent meta-analysis showed that, up until 2017 at least, there was no evidence that zinc gluconate lozenges are less effective than zinc acetate lozenges [5].
When discussing treatment effects, the size of the effect and its confidence interval should be considered [6]. Thereby a critically-minded reader can form his or her own opinion about whether the treatment effect is relevant. The data of 7 placebo-controlled double-blind RCTs showed that zinc acetate and zinc gluconate lozenges shortened common cold duration on average by 33% (95% CI 21% to 45%) [5]. Individual-patient data were available for 3 zinc acetate lozenge trials and on the basis of these findings, zinc lozenges shortened the duration of colds by 2.7 days (95% CI 1.8 to 3.3 days) [7], and increased the rate of recovery by RR = 3....
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None declared.