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Do "Natural" Cold Remedies Work?

Many "natural" cold remedies promise to chase away the sniffles if you just pop some vitamin C, take Echinacea or zinc, or heat up some chicken soup. And the makers of these products may mention that taking their secret remedy before the first little tickle in your nose may have helped you avoid the cold altogether.

But, never mind the fervor with which these cold remedies are offered. Do they actually work? WebMD turned to three top experts who have studied the cold virus for decades.

First, the really bad news: "You can't cure a cold," says David A. Blandino, MD, chairman of family and community medicine at the University of Pennsylvania Medical Center Shadyside Hospital in Pittsburgh.

But you may be able to shorten one. Here's the scorecard on whether natural cold remedies such as vitamins and supplements get a thumbs up or thumbs down.

Natural Cold Remedies: The Rundown

1. Zinc: The mineral zinc, available in over-the-counter lozenges, nasal sprays, and gels, may work by preventing the formation of proteins needed by a cold virus to reproduce.

Despite the hoopla about zinc for treatment of colds, scientific studies are scarce, says Jack M. Gwaltney, MD, professor emeritus of internal medicine at the University of Virginia and a longtime cold researcher. Gwaltney tells WebMD that he and his colleagues could find only 14 published studies that looked at zinc the scientific way, with both placebo and treatment groups. Zinc lozenges, they conclude, have no effect. One well-designed study reported a positive effect on treating a cold with zinc nasal gel. But the study results have not yet been replicated, Gwaltney says.

2. Vitamin C: For decades, believers in vitamin C have said taking this vitamin supplement can nip a cold in the bud. The claim is partially triggered by lab studies that find vitamin C affects resistance to virus in animal studies.

But in people? Experts disagree on this slightly, but lean toward the negative. Some, including Blandino, say vitamin C has not been proven to shorten the duration of a cold. One 2007 study showed that if vitamin C is taken after a cold begins, it doesn't shorten the cold or make it less severe. But when it is taken daily as a preventive treatment - not just after that first sniffle - it can very slightly shorten cold duration, by about 8 percent in adults and by about 14 percent in children.

Very highly fit people - marathon runners, for instance - might cut their risk of a cold in half by taking the vitamin, the study also showed. But Gwaltney does not agree. "The weight of scientific evidence and the well-done studies indicate vitamin C does not prevent colds," says Gwaltney. "It may have some mild effect on treating colds."

3. Echinacea: The herbal supplement Echinacea, like Vitamin C, sparks controversy among cold experts. Advocates say it's an immune booster with antiviral properties and other benefits, so it's good at preventing colds. However, two recent studies on the natural remedy have yielded conflicting conclusions. In one 2007 study, University of Connecticut researchers concluded that Echinacea decreases the odds of developing a cold by 58 percent and reduces its duration by 1.4 days. But a previous study, conducted by Gwaltney's colleagues at the University of Virginia and published in 2005 in The New England Journal of Medicine, showed no benefit from the herb in either reducing the severity of a cold infection or preventing a cold.

Echinacea drew a "no" vote from our three experts -- Gwaltney, Blandino, and Owen Hendley, MD, professor of pediatrics in the division of infectious diseases at the University of Virginia, Charlottesvile.

4. Chicken Soup: Advocates of hot chicken soup, long offered as a cold remedy, say it may help soothe inflammation that can make the symptoms worse. The problem with proving scientifically that chicken soup works, says Gwaltney, is finding a legitimate placebo food to study against it in a scientific way. "We were contacted by a soup manufacturer to do a study on chicken soup," he tells WebMD. "We thought we could use another hot beverage" for placebo, he says. "But it's got to look, smell, and taste [like chicken soup]." They didn't find anything that measured up. Gwaltney calls chicken soup "a waste of time."

That's despite the well-publicized report published in 2000 in which researchers reported that chicken soup, which they studied in the laboratory, may have an anti-inflammatory effect on easing symptoms of upper respiratory infections. But the report doesn't prove chicken soup does anything for cold symptoms, Gwaltney says, because it didn't include a test of people nor include a placebo for comparison.

Although chicken soup may not actively fight a cold, it can help fight dehydration that can occur when you have a cold or the flu.

Preventing a Cold: Does Anything Really Work?
Hand washing has long been touted as a way to prevent a cold during cold and flu season, and experts agree that is wise. But here's the newest twist: Paying attention to where you put your hands - and scheduling your hand washing around where your hands have been, rather than the clock - appear to be important, too. That's because cold viruses may linger on surfaces longer than suspected, Hendley and his colleagues have discovered.

Hendley and other University of Virginia researchers did a study published in 2007 of people with a cold who stayed overnight in a hotel. "We went in the next day and swabbed 10 sites they had touched," Hendley says.

"We found about 30 or 40 percent of the sites had virus on them." He's talking about surfaces such as light switches and TV remote controls. "A third of the time, the virus was still there," Hendley says of the site samples. "Now we are trying to figure out, is it still infectious?" The hotel study didn't go there, but that study is under way.

Until more research is in, Gwaltney suggests hand washing after touching potentially germy surfaces, rather than adhering to the often-suggested advice of hand washing throughout the day no matter what you've touched. Rhinoviruses cause about half of all colds in adults, Hendley says. You acquire the virus by getting it on your hand and then touching your nose or eyes, he says. "The virus doesn't usually go through the air," Hendley says. "You usually get it on the finger and you inoculate yourself. Just being in the air space [with an infected person or the virus] is not enough."

Besides hand washing, breathing in humidified air and increasing your fluid intake may also help, Blandino says. Whatever natural remedy you use, the effects on the cold will be minimal, cautions Gwaltney. Of natural cold remedies, he says: "They're not as effective as commercial cold remedies" such as decongestant, antihistamines, and non-steroidal anti-inflammatory drugs. Patience could pay off, too, Blandino says. "You can't cure the cold," he says. "[But] most of them are gone within 10 days."
By Kathleen Doheny
Reviewed by Louise Chang
©2005-2008 WebMD, LLC. All rights reserved

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