July 19, 2010 -- Just over a year ago, the FDA warned that zinc-containing intranasal cold remedies might cause loss of sense of smell.

Now a researcher who has long argued that the sprays were harmful says he has scientific evidence to back up the claim.

Last summer, the FDA warned consumers to stop using three zinc-containing Zicam products: Zicam Cold Remedy Nasal Gel, Zicam Cold Remedy Swabs, and Zicam Cold Remedy Swabs for kids. The federal regulators cited 130 reports of loss of sense of smell among users of the products.

Zicam manufacturer Matrixx Initiatives pulled the three products from the shelves, but the company maintains that there is no link between their use and loss of smell.

In the newly reported analysis, researchers applied a statistical method used to establish a cause-and-effect link between an environmental exposure and development of a disease in an effort to confirm that zinc-containing nasal products can cause loss of sense of smell, known medically as anosmia.

University of California, San Diego professor Terence M. Davidson, MD, says the analysis supports the hypothesis.

He adds that the effectiveness of zinc-containing products for preventing or shortening the duration of colds has never been proven.

“Given that they do absolutely no good for colds and given that there is potential for harm, I see no point in putting any zinc gluconate products in the nose,” Davidson tells WebMD.