Considered potentially toxic by the Environmental Protection Agency and the Occupational Safety and Health Administration, silver enjoys a lustrous reputation in alternative health circles. Proponents believe that silver in its many forms can kill germs, boost the immune system and generally improve health.
Colloidal silver -- water infused with particles of the metal -- is an especially popular option for silver aficionados. You can buy gadgets over the Internet to make batches of colloidal silver at home, or you can buy ready-made products at health food stores and drugstores.
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Sovereign Silver, a ready-made colloidal silver product manufactured by Natural-Immunogenics Corp., is available in a gel, spray and a dropper-top bottle. The label from the dropper-top bottle instructs users to swallow six droppers full -- the equivalent of one teaspoon -- every day. That adds up to 50 micrograms of silver. (A microgram is one-millionth of a gram.) A 60-milliliter bottle, enough to last 12 days when used as directed, costs about $15.
Silver Shield, sold over the Internet by Nature's Sunshine, contains 90 micrograms of silver per teaspoon. Users are instructed to take three teaspoonfuls a day with meals. If one followed those directions, a 118-milliliter bottle -- which sells for about $21 -- would last about eight days.
The claims: The label for Sovereign Silver says that it's "the first line of defense for immune threats."
Robert Scott Bell, a homeopathic practitioner and a paid consultant for Natural-Immunogenics, says that the company can't make more specific health claims for fear of action from the Food and Drug Administration. The FDA ruled in 1999 that colloidal silver products couldn't claim to treat any specific illness because of a lack of evidence.
But Bell does feel safe talking about colloidal silver products in general. He says silver is a highly effective germ killer that can both prevent and treat all sorts of infectious diseases. "There's no bacteria or virus that can withstand silver in its active form," he says.
The Nature's Sunshine website says that colloidal silver is a "near perfect antibiotic" that protects against colds, flu and other infectious diseases with "no known bad side effects."
The Natural Health and Longevity Resource Center website, an informational site that doesn't sell products, says that colloidal silver is "reputed" to be helpful for an impressive list of ills, including AIDS, cancer, malaria and athlete's foot.
The bottom line: Silver undoubtedly has some germ-killing powers. Silver compounds are sometimes applied to bandages to prevent infections, and silver is also used to treat drinking water.
But there's no evidence that taking colloidal silver can do anything to fight disease or improve health, says Dr. Edmund Pribitkin, a professor of otolaryngology at Thomas Jefferson University in Philadelphia.
"Those studies haven't been done," says Pribitkin, who co-wrote a 2008 article on silver nasal sprays and colloidal silver published in the Ear, Nose and Throat Journal. In his view, just because something kills germs on contact doesn't mean it will fight infections inside the body. He notes that sulfuric acid kills germs too, but nobody touts it as a health tonic.
If colloidal silver really were some sort of super bug-fighter, it would have been embraced by mainstream medicine long ago, Pribitkin says. In fact, he says, he'd be one of the first in line. "I've had a terrible cold for the last week. I'd love to be able to order something over the Internet that would make me feel better."
Contrary to claims made by some websites, silver in large enough doses can cause side effects. In rare cases, it can collect under the skin and react with sunlight to create a permanent bluish tint, a condition known as argyria. Although unsightly, argyria is not dangerous. Victims include Stan Jones, a frequent candidate for office in Montana who has publicly stated that he turned blue after taking colloidal silver in preparation for Y2K. In 2002, he speculated on "The Daily Show" that Montana was ready "for a senator of color."
A report from the National Institutes of Health warns that large doses of colloidal silver could cause seizures, kidney damage, stomach trouble, headaches and fatigue.
The EPA estimates that a person could safely take up to .005 milligrams of silver per kilogram of body weight each day without side effects. Because almost no research has ever been conducted on colloidal silver, the agency warns that this figure is a very rough guess. But, by that standard, a 150-pound (68-kilogram) person could safely take seven times the recommended dose of Sovereign Silver or 1.2 times the recommended dose of Silver Shield.
Homemade batches of colloidal silver are a little less predictable and potentially more dangerous. Dr. Christopher Baker, a pediatric pulmonologist at the Children's Hospital in Denver, recently treated an 11-year-old boy who had turned slightly blue after being given homemade colloidal silver for his cystic fibrosis. "People are spending a lot of money on something that has never been proven to work," he says.
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