Duration and severity of symptoms and levels of plasma interleukin-1 receptor antagonist, soluble tumor necrosis factor receptor, and adhesion molecules in patients with common cold treated with zinc acetate

Background. Zinc lozenges have been used for treatment of the common cold; however, the results remain controversial. Methods. Fifty ambulatory volunteers were recruited within 24 h of developing symptoms of the common cold for a randomized, double-blind, placebo-controlled trial of zinc. Participants took 1 lozenge containing 13.3 mg of zinc (as zinc acetate) or placebo every 2-3 h while awake. The subjective scores for common cold symptoms were recorded daily. Plasma zinc, soluble interleukin (IL)-1 receptor antagonist (sIL-1ra), soluble tumor necrosis factor receptor 1, soluble vascular endothelial cell adhesion molecule, and soluble intercellular adhesion molecule (sICAM)-1 were assayed on days 1 and 5. Results. Compared with the placebo group, the zinc group had a shorter mean overall duration of cold (4.0 vs. 7.1 days; P <.0001) and shorter durations of cough (2.1 vs. 5.0 days; P < .0001) and nasal discharge (3.0 vs. 4.5 days, P = .02). Blinding of subjects was adequate, and adverse effects were comparable in the 2 groups. Symptom severity scores were decreased significantly in the zinc group. Mean changes in plasma levels of zinc, sIL-1ra, and ICAM-1 differed significantly between groups. Conclusion. Administration of zinc lozenges was associated with reduced duration and severity of cold symptoms. We related the improvement in cold symptoms to the antioxidant and anti- inflammatory properties of zinc.