"Theres still no cure for the common cold but there may be a way to shorten its misery A new study suggests that higher doses of zinc lozenges in certain formulations may cut the length of colds by more than  percent. Researcher Dr. Harri Hemila of the University of Helsinki in Finland reviewed  placebocontrolled trials examining the effect of zinc lozenges on cold infections. Three of them found that zinc acetate in daily doses of more than  milligrams mg shortened colds duration by  percent on average. Five trials using zinc salts other than acetate in daily doses greater than  mg shortened colds by an average of  percent while another five using less than  mg per day produced no effect. Much of the variation in the published study findings can be explained by the daily dose of zinc administered in the zinc lozenges said Hemila who funded the research himself. When focusing on those studies which have used large daily doses of zinc there is strong evidence that zinc lozenges shorten the duration of colds. The study is published in The Open Respiratory Medicine Journal. Despite the popularity of zinc supplements controversy over their effectiveness has continued since a muchpublicized  study first suggested a coldlimiting effect. Allowing the lozenge to dissolve instead of swallowing it seemed to provide a therapeutic effect. Since then more than a dozen studies have been carried out but data on the trace minerals effectiveness has been mixed. All of the trials examined by Hemila compared zinc lozenges to placebos. While surprised to note how strong the correlation was between daily doses of zinc and its effect on colds duration he said he and his colleagues still dont know why it seems to work. In the evidencebased medicine framework we are primarily interested in the question whether there is an effect and how great whereas the mechanism of the effect is a secondary issue he said. No prior studies showed zinc lozenge use  even up to  mg per day  might cause harm aside from bad taste or constipation Hemila said and the most recent trial on zinc acetate indicated no significant differences between zinc and placebo groups in adverse effects even though the daily zinc dose was  mg. Dr. Lisa Winston an epidemiologist at San Francisco General Hospital praised the study as a pretty good synthesis of the data although she noted that the trials Hemila reviewed involved small numbers of participants. Its an area of controversy and question . . . but I dont think the evidence is strong enough nor do I think the author is suggesting that we can base clinical practice on it said Winston also an associate professor in the University of CaliforniaSan Francisco Department of Medicine. I would tell my patients we still dont have a cure for the common cold and we dont know if zinc works. More information The U.S. National Library of Medicine has more about the common cold http SOURCES Harri Hemila M.D. Ph.D. researcher department of public health University of Helsinki Finland Lisa Winston M.D. associate professor University of California San Francisco Department of Medicine and vice chief inpatient medical services and hospital epidemiologist San Francisco General Hospital  The Open Respiratory Medicine Journal"