Drugs with zinc have been found to be "especially effective" in treating common cold symptoms, a new study published in The Cochrane Library found.
The study, covering 15 different randomized controlled trials of about 1,400 people, compared with the results of cold medicines that contain zinc with a zinc-free placebo.
The researchers concluded that participants who took a medication liquid or solid zinc containing cold symptoms were less severe for shorter periods than those taking placebo.
"Zinc (tablets or syrup) is beneficial in reducing the duration and severity of common cold in healthy people when taken within 24 hours of onset of symptoms," the researchers wrote Meenu Singh and Rashmi Das Department Pediatrics at the Graduate Institute of Medical Education and Research in Chandigarh, India.
There is no proven cure for the common cold, mostly caused by rhinovirus infection, and is one of the leading causes of doctor visits and absences from school and work.
However, the persistent use of zinc cold medicine may reduce cough, runny nose, sneezing and other cold symptoms that hinder children, according to the study.
"When completed at least five months, [zinc] reduces the incidence of colds, truancy and prescribing antibiotics for children," wrote the authors.
Despite their findings, researchers were hesitant to recommend specific drugs and their use.
"It is difficult to make firm recommendations on dosage, formulation and duration to be used," they said. In addition, zinc lozenges may have unpleasant side effects such as "bad taste and nausea."
Further research is needed to determine the "optimal duration of treatment, the dosages and formulations of zinc that produce clinical benefits without increasing adverse effects," the study said.
