Zinc

Zinc is an essential micronutrient for human health:

Zinc is vital for many biological functions including healthy immune response. A review of 13 trials looking at the link between zinc and treatment of the common cold in adults suggests zinc may be mildly effective for management of colds. The review did not find any trials which evaluated zinc in cold prevention. Compared to placebo, nasal sprays, were found to reduce the duration and severity of a cold in 4 trials and 2 trials, respectively. Lozenges, small medicated tablets intended to be dissolved slowly in the mouth (like a cough drop), containing at least 13mg of zinc are recommended every 2 hours during a cold episode but individuals may experience bitter taste, nausea, and impaired smell and taste while taking zinc. Zinc use should be stopped after 6-8 weeks or the individual may become copper deficient. In 5 trials lozenges were found to reduce cold symptom duration and severity. Lozenges containing 13-24 mg of zinc taken every 2 hours were associated with a reduced cold duration of 1.3-6.9 days. Severity also improved. Results were difficult to decipher in the studies due to dosing and formulation questions. (3)