A U.S. study found that taking large doses of zinc can shorten the course of the disease in common colds. Moreover, experienced subjects taking zinc tablets, the symptoms were less.
It has long been debated whether zinc can have a beneficial effect on colds. Previously, five clinical studies provided evidence for such an assertion, while five other studies have found no such effect. It has been argued that the studies that showed the income used at low doses of zinc.
In the latest issue of the Annals of Internal Medicine described a study in which participants had a high intake of zinc. 50 students or employees at Wayne University in Detroit who had had symptoms of colds less than 24 hours attended. Half received sham pill (placebo) while the rest received pills who contained 12.8 g of zinc. These pills should be taken every three hours as long as the symptoms lasted. (12 g of zinc is recommended daily intake in the Nordic countries).
There were significant differences in the duration of colds in the two groups. In the group receiving zinc, colds lasted on average for 4.5 days, while it lasted for eight days in that receiving placebo. The greatest difference was found in duration of cough. For the placebo, group did cough for an average of six days, but it lasted for three days for that receiving zinc.
The researchers are uncertain what mechanism behind the observed effects. In the study, it was noted that the amount of cytokines, which is substances the body produced during infections was lower in patients treated with zinc. The results are not so statistically significant that one can rule out that due to chance. So the question is still open.
Zinc supplements in this set is not completely side effect free. Some of the participants who received zinc reported dry mouth and constipation. There were no reports of serious side effects.
It is difficult to draw any clear conclusion of such an inquiry, especially when past performance varies as much as they do. Zinc taken up in the body part at the expense of iron, and an intake above 200 mg. today, could have adverse effect on iron absorption. Larger doses may cause serious side effects. Zinc supplement sold in pharmacies on prescription and is not intended for the treatment of colds. Therefore, pocket doctor not recommended zinc supplements for this purpose before it reaches further research.