Alternative Treatments Used For The Common Cold - Zinc Preparations

Zinc Preparations

Zinc deficiency impairs immune function. It has been suggested that zinc may inhibit rhinovirus replication and reduce inflammation, but any mechanism of action is not presently understood. A systematic review by the Cochrane Collaboration, last updated in 2011, concludes that zinc supplements can somewhat reduce the severity and duration of common cold symptoms when taken by otherwise healthy adults within 24 hours of onset of symptoms, and that supplementation for at least five months reduces incidence. Optimum dosing and formulation have not been determined. The studies included in the review used a variety of forms and doses of zinc, including zinc gluconate or zinc acetate lozenges and zinc sulfate syrup. The doses ranged from 30 to 160 milligrams per day.

There are concerns regarding the safety of long-term use of cold preparations in persons who are haemochromatosis heterozygotes. Use of high doses of zinc for more than two weeks may cause copper deficiency, which leads to anemia. Other adverse events of high doses of zinc include nausea, vomiting gastrointestinal discomfort, headache, drowsiness, unpleasant taste, taste distortion, abdominal cramping, and diarrhea. Nasally applied zinc gels may lead to loss of sense of smell. The FDA therefore discourages their use.