The report reviews more than two decades of laboratory and clinical research into the medicinal value of zinc, before concluding that zinc gluconate, the active ingredient found in popular over-the-counter (OTC) cold products, effectively reduces the duration of the cold and the severity of cold symptoms.
Author Darrell Hulisz, associate professor of family medicine at the Case Western Reserve University School of Medicine, noted that there had recently been a series of strong, peer-reviewed clinical studies of zinc gluconate that linked this ingredient with a significant reduction in the duration of the common cold, as well as the severity of cold symptoms such as sore throat, stuffy nose, sneezing, coughing, and congestion.
"It is important to note that the products were most successful when administered within 24 hours of symptom onset," he wrote.
He added that clinical and laboratory evaluations are now needed to further define the role of ionic zinc for the prevention and treatment of the common cold and to clarify the biochemical mechanisms through which zinc exerts its symptom-relieving effects.
Dr. Hulisz reviewed data sources published between 1980 and 2003.
Supplemental zinc, is often taken to prevent or treat colds, at doses of up to 100 mg per day and is sold in various forms including capsules, liquid and lozenges.
According to the National Institutes of Health, people suffer from an estimated one billion colds in the US each year, causing 300 million days of restricted activity and 22 million lost days of school and work. Adults average about two to four colds a year, although the range varies widely. The US Centers for Disease Control and Prevention estimates the average cold will last about nine to 12 days.