Last Wednesday I wrote about the role that vitamin C may have in the treatment of cancer. Of course vitamin C may have other potential benefits for the body too, and is sometimes said to be a useful remedy for the common cold in high doses. Another nutrient that has some reputation for potential benefit here is zinc. In natural medicine, it is sometimes recommended that individual suck zinc lozenges to hasten common cold healing. There is indeed some evidence to suggest that there is merit in this approach that dates back more than 20 years.
I was interested to read about another study, this one published earlier this year, in which zinc lozenges were tried in individuals with the common cold. Here, zinc acetate lozenges (13.3 mg of zinc acetate per lozenge) were used (previous studies have tended to use zinc acetate or zinc gluconate). Individuals were randomised to suck zinc lozenges or placebo lozenges every 2-3 hours while wake, starting within a day of developing cold symptoms.
Compared to the individuals sucking placebo lozenges, those sucking zinc lozenges:
Had cough symptoms for a shorter period of time (2.1 days versus 5 days)
Had nasal discharge for a shorter period of time (3 days versus 4.5 days)
Overall, had cold symptoms for a shorter period of time (4 days versus 7.1 days)
Symptom severity scores were lower in the zinc lozenge-taking group, too.
The authors of this study put the therapeutic properties of zinc in this context down to this minerals antioxidant and anti-inflammatory properties. However, it may also be that zinc can exert benefits through an ability to inhibit the common cold virus (rhinovirus) [3], as well as through some ability to affect the immune response.
However they work, there is now quite a body of evidence that suggests that zinc lozenges have real value in the treatment of the common cold.
References:
1. Eby GA, et al. Reduction in duration of common colds by zinc gluconate lozenges in a double-blind study. Antimicrob Agents Chemother 1984;25:20-24
2. Prasad AS, et al. 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. J nfect Dis 2008; 197(6):795-802
3. Korant BD, et al. Inhibition by zinc of rhinovirus protein cleavage: interaction of zinc with capsid polypeptides. J Virol. 1976;18(1):298-306.
