—Dr Trempe seems unaware of a number of other clinical studies that have been published, at least in the popular press.1 He exaggerates by calling 200 mg of zinc acetate "toxic." Not only did we not see evidence of toxic effects in our study, but also some physicians have given similar amounts to patients for many years without evidence of "toxicity."2 Zinc sulfate is an emetic, and it is unlikely that one could ingest a truly toxic dose repeatedly. To have megaloblastic anemia, large amounts of zinc have to be ingested and retained by a patient.3Although some of the subjects in the serum ceruloplasmin study4 later participated in our clinical trial, no subject was known to be taking "large amounts of zinc" when the serum samples that we studied were obtained.
Newsome DA. Zinc and Macular Degeneration-Reply. Arch Ophthalmol. 1992;110(11):1517. doi:10.1001/archopht.1992.01080230015003