Zinc lozenges and vitamin C for high-performance athletes: [eLetter]

In their International Olympic Committee consensus statement, Maughan et al. reviewed the evidence for dietary supplements for high-performance athletes.
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]”. This statement was based on their reading of the Cochrane review (2013) by Singh and Das, which was withdrawn in 2015 because of plagiarism. In addition, the same Cochrane review had a large number of other severe problems. 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...