There are studies that show that the use of zinc supplements decreases the duration of colds and the severity of their associated symptoms. Sucking zinc tablets in divided doses throughout the day is very effective when there is throat irritation and infection, since it has localized microbicidal effect. It also preserves the integrity of the membranes, by decreasing the damage generated by free radicals generated during inflammation. In cases of colds, zinc makes it difficult for the virus to bind to the surface of the nasal mucosa.
Thus, zinc is a very suitable supplement in cases of colds, flu and infections of the upper respiratory tract.
Reference: “Zinc and immune function: the biological basis of altered resistance to infection” Anuraj H Shankar and Ananda S Prasad, Am J Clin Nutr 1998;68 (suppl):447S-63S