Zinc supplements, a popular if controversial treatment for colds in the United States, are effective in treating cases of severe pneumonia, researchers reported this week.

In a study among hospitalized children in Bangladesh, zinc added to a standard antibiotic helped children recover faster. Perhaps more significantly, it prevented outright treatment failures - suggesting that doctors may not have to switch antibiotics as often to get results.

By reducing a child's exposure to antibiotics, doctors hope they will be able to stem the worrisome growth of antibiotic-resistant diseases, which are fast becoming a public health scourge worldwide.

With publication of the latest study Thursday, led by doctors at the Johns Hopkins Bloomberg School of Public Health, zinc looms as a potentially powerful tool in the fight against infectious diseases in the Third World.

Previous studies had shown that zinc is effective in preventing and treating diarrheal diseases, the second-leading killer of children worldwide. Research had also shown that the trace mineral prevents pneumonia, the No. 1 killer.

"It was beyond dispute that zinc helps to prevent pneumonia," said Dr. W. Abdullah Brooks, an infectious disease researcher at the Hopkins public health school and lead author of the study. "No one showed that it had a treatment benefit."

An estimated 2 million children die of pneumonia each year, compared to 1.7 million who succumb to diarrheal disease.

The study appeared the same week that the World Health Organization and UNICEF jointly recommended zinc as part of an international strategy against diarrheal disease. The other key element is oral rehydration therapy, a mineral-rich solution that prevents dehydration.

Dr. Robert Black, director of international health at Hopkins, said zinc plays an important role in the immune system.

Children who have been subjects in diarrhea and pneumonia studies come from populations that are generally deficient in zinc, he said. In those trials, he said, zinc therapy may have worked by correcting the deficiencies, he said.

It is not clear whether zinc supplements can help people who already get enough from their diets, Black said.

Scientists, including those taking part in the study, appear divided on whether zinc's only role is correcting a nutritional deficit. Admitting the issue is far from settled, Brooks said he believes that zinc may act more like a drug - boosting immunity by other means.

Zinc is present in many edible plants, but exists in much higher concentrations in meat. In the United States, where zinc deficiency is rare, people derive most of their zinc from poultry and red meat.

The study does not settle the debate over zinc as a cold fighter. In 2002, Americans spent $58 million on zinc lozenges and supplements, making it the fourth most popular dietary supplement, according to the Nutrition Business Journal.

According to the National Institutes of Health, researchers have come to different conclusions about zinc's power against the common cold.

A study of 100 employees at the Cleveland Clinic found that zinc reduced the duration of colds by half. Others have found some preparations used in zinc lozenges were effective while others were not.

But some studies found that the supplements, no matter how they were made, had no effect.

From Healthy.net