Zinc Gluconate - Zinc and The Common Cold

Zinc and The Common Cold

A 2011 systematic meta analysis of studies conducted by the Cochrane Collaboration indicates that zinc lozenges definitively shorten the duration and severity of cold symptoms but offers no recommendations as to dosage. Many over the counter zinc medications may be less effective or ineffective because they do not contain the optimum mix of ingredients. This variety of formulations has also been implicated in the prior lack of success in determining the effectiveness of zinc medicines. Methodological weaknesses are also thought to have contributed to the mixed results of previous studies (see below). The 2011 Cochrane review is widely regarded as the most authoritative assessment to date of the effectiveness of zinc as a treatment for the common cold. It is suspected that zinc acetate lozenges shorten the duration of cold symptoms by reducing inflammatory cytokines.

Zinc administered within 24 hours of onset of symptoms reduces the duration and severity of the common cold in healthy people.

When supplemented for at least five months, it reduces cold incidence, school absenteeism and prescription of antibiotics in children.

There is potential for zinc lozenges to produce side effects. In view of this and the differences in study populations, dosages, formulations and duration of treatment, it is difficult to make firm recommendations about the dose, formulation and duration that should be used.

Before 2011, research on the zinc and the common cold has been inconsistent, and a number of studies have failed to find any benefit. A 2000 systematic review by the Cochrane Library referred to the evidence of benefit as inconclusive. The Harvard Family Health Guide stated in 2001 that one study suggested that "zinc lozenges have little, if any, beneficial effect on the treatment of the common cold." A 2003 review in the Journal of American Pharmacists Association determined that the majority of studies supported the value of zinc in reducing the duration and severity of symptoms of the common cold when administered within 24 hours of the onset of common cold symptoms. Another systematic review, published in 2006 in Clinical Infectious Diseases, found that many of the studies of zinc in the common cold suffered from methodologic flaws; restricting the analysis to well designed studies, the authors concluded that the therapeutic effectiveness of zinc lozenges has yet to be established.