Common Cold

Zinc Helps Common Cold: 8/15/00 Ann Intern Med study 25 adults taking Zn acetate dihydrate Q2-3 hrs for 4-5 days had colds disappear in under 5 days vs. 8 days for controls. Did get constipation and mouth dryness and other studies report diarrhea and nausea.

Zinc No Benefit: Study of 249 school children treated with 10mg lozenges 5-6 times per day within 24 hours of cold. Placebo did just as well. Zinc caused bad taste, nausea, mouth discomfort, and diarrhea. JAMA 6/98 279:1999-2000.

Review Says Zinc Helps: 7 DB studies treated within 24-48 hr sucking a lozenge every 2 hours while awake with at least 13.3 mg zinc/lozenge. Some bad taste and nausea. Can Fam Physician 5/98, 44:1037-42

Review Says Maybe to Zinc: 8 DB studies, 4 found effective. Benefit appears maximal if started immediately. Citric acid or tartaric acid may reduce efficacy due to chelation. Studies are with zinc gluconate. Ann Pharmacother 1/98, 32:63-9

Review Says Depends on the Zinc Lozenges: Says lozenges that released Zn++ ions shorten colds but ones that released negatively charged zinc species at physiologic pH lengthened colds. Claims high zinc ion availability zinc acetate lozenges beneficial. J Antimicrob Chemother 10/97, 40:483-93.

Review Says No Clear Benefit Zinc: 2 of the 8 DB studies eliminated due to innoculation design. No evidence from analysis of six remaining that reduce duration. Arch Int Med 11/10/97

Zinc Helped: Taking at first sign of coughing and congestion, cold lasted four days, vs. 8. Annals Int Med 2000;133:245-52

Zinc Reduced Lower Respiratory: Zinc supplementation reduced LRI by 45%. Lancet 1998;352:119

Common Cold Reduced by Nasal Spray: 80 adults DB PC zinc nasal spray four times a day. Duration 4.3 days vs. 6.0 placebo. Effect of zinc gluconicum nasal gel on the duration and symptom severity of the common cold in otherwise healthy adults. Mossad SB. QJM 2003 Jan;96(1):35-43, Cleveland Clinic

Thomas E. Radecki, M.D., J.D.

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