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Zinc lozenges may be ineffective against symptoms of common cold

SHARE Zinc lozenges may be ineffective against symptoms of common cold

The controversial researcher who started the zinc lozenges craze says a new study indicates they are ineffective against cold symptoms in children and teenagers.

But the researcher, Dr. Michael L. Macknin of the Cleveland Clinic Foundation, said that the amount of zinc in the lozenges studied may have been too small or the cherry flavoring somehow inactivated the zinc.The zinc fad began in 1996, when Macknin's study of 100 adults was published in the Annals of Internal Medicine. Cold sufferers who took the lemon-lime lozenges got over their symptoms more quickly.

The pediatrician later made $145,000 on the sale of stock in Quigley Corp., the Doylestown, Pa., maker of ColdEeze zinc lozenges.

His latest study was also supported by a grant from Quigley and was published in the Journal of the American Medical Association.

The findings were quickly challenged by Quigley.

A total of 249 suburban Cleveland students in grades one through 12 were recruited within 24 hours of developing a cold. Half took 10-milligram zinc lozenges five or six times a day; the other half took placebos.

The sneezing, coughing, headaches and other symptoms were no different between the two groups, and the duration of the illness was the same.

Studies with adults used dosages higher than 10 milligrams, but the strength was reduced for the youngsters.

In an accompanying editorial, a researcher said the lack of any theoretical basis for why zinc might work "is troublesome and reminiscent of prior attempts to cure the common cold" with substances such as vitamins C and A.

"The search for the `magic bullet' that will relieve the multitude of symptoms associated with the common cold continues," wrote Dr. Anne Gadomski of the Research Institute at Bassett Hospital in Cooperstown, N.Y.

In 10 previous studies among adults, five found that zinc helped relieve symptoms, while the other five showed no effect.

In a statement this week, Quigley said Macknin violated controls set up before the research, invalidating the findings.

"The data that resulted from the study provides no meaningful conclusion," Quigley said.

It said 83 of the 249 students in the study should have been disqualified because they were on other medication, had illnesses in addition to or other than a cold, or in violated the research guidelines in other ways.

The company said it plans to repeat the study.