Medical uses of silver

Colloidal silver is a liquid suspension of microscopic particles of silver. A colloid is technically defined as particles which remain suspended without forming an ionic, or dissolved solution. The broader commercial definition of "colloidal silver" includes products that contain various concentrations of ionic silver, silver colloids, ionic silver compounds or silver proteins in purified water. Colloidal silver with concentrations of 30 parts per million (ppm) or less are typically manufactured using an electrolysis process, whereas colloidal silver with higher concentrations of 50 ppm or more are usually either silver compounds such as silver chloride and silver iodide or are solutions that have been bound with a protein to disperse the particles. Silver ions are reported to kill bacteria via the oligodynamic effect by inhibiting the expression of enzymes and other proteins essential to ATP production.

History and Applications

Prior to 1938, colloidal silver was widely promoted as a "cure-all", and silver products were used by physicians as topical antibiotics. However, with the development more effective, less expensive antibiotics such as penicillin and sulfanilamide, medical use of colloidal silver ceased. From approximately 1990, there has been a resurgence of the promotion of colloidal silver as an alternative medicine treatment, marketed with claims that it can prevent or treat numerous diseases.

Colloidal silver products are available at most health food stores, and are marketed over the Internet as a dietary supplement for the prevention of colds and flu, and the treatment of more serious conditions such as diabetes, cancer, chronic fatigue syndrome, HIV/AIDS, and tuberculosis, among other diseases. Colloidal silver has been found to lack any antimicrobial effect, and there is no medical evidence that colloidal silver is effective for any of these claimed indications.

Currently, there are no evidence-based medical uses for colloidal silver. There are no clinical studies in humans demonstrating effectivness, and several reports of toxicity.

Colloidal Silver as Alternative Medicine

Main article: Alternative medicine

The use of colloidal silver as an alternative medicine is the subject of strong and emotional debate.

The antimicrobial properties of many forms of topically applied silver has been well established. For example silver sulfadiazine cream and silver-nylon dressings are widely used in hospital burns units to reduce the risk of infection and promote healing The use of colloidal silver tablets in the successful treatment of 87 peptic ulcer patients prior to the discovery that peptic ulcer is caused by bacteria also indicated that ingested silver may have anti-bacterial properties. The usage of silver in such applications has lead many proponents to believe that silver may have similar effects in the human body when consumed as the easily made aqueous solution commonly referred to as colloidal silver.

A prominant claim by the opponents of colloidal silver is that it is toxic and causes neurological damage. This is disputed even within the medical community. A March 2007 review in Critical Reviews in Toxicology stated 'available evidence from experimental animal studies and human clinical reports has failed to unequivocally establish that it enters tissues of the central nervous system or is a cause of neurotoxic damage'.

Claims of health improvements following the use of colloidal silver are largely anecdotal and are not accepted as medical evidence but doctors have speculated 'the potential benefits might be worthy of further exploration'. Doctors recently reported the case of 'sustained improvement in the symptoms' of a child with cystic fibrosis coinciding with the use of colloidal silver purchased from a local health shop.

The emergence of colloidal silver as an alternative medicine received a boost when Dr Robert O Becker, an orthopedic surgeon, published The Body Electric in 1985. In this book he described a case of accelerated healing after applying 2 silver wires to a wound. The wires had a small electric current applied and released silver ions into the moist wound.

Another widely quoted advocate of colloidal silver was the similarly named Dr Bob Becka physicist who created the so-called Beck Protocol, a 4-step alternative medicine therapy comprising colloidal silver, non invasive blood electrification, magnetic pulsing, and drinking ozonated water. He claimed to have invented the modern process of making ionic colloidal silver water in the early 1990's by using low voltage electrolysis to dissolve silver wires into water.

Toxicities and interactions

Main article: Argyria

Excessive intake of silver products may result in a condition known as argyria, one symptom of which is blue or gray discoloration of the skin. The discoloration occurs when silver is deposited in the skin and then darkened by sunlight, just as silver particles in photographic film darken when exposed to sunlight. Localized argyria can occur as a result of topical use of silver-containing remedies, while generalized argyria results from the ingestion of colloidal silver. Arygria is usually permanent, and there is no known effective treatment. While argyria is usually benign and limited to skin discoloration, there are isolated reports of more serious neurologic, renal, or hepatic complications. A death has been reported in the medical literature as a result of colloidal silver use; in that case, a 71-year-old man developed status epilepticus which the authors felt was due to silver toxicity.

A number of case reports describe argyria after ingestion of colloidal silver marketed as an alternative-medicine treatment. Colloidal silver may theoretically interact with some medications, including tetracycline and quinolone antibiotics and penicillamine, reducing the effectiveness of those medications.

Government regulation

In August 1999, the U.S. Food and Drug Administration (FDA) banned colloidal silver sellers from claiming any therapeutic value for the product, noting that such products were being marketed for numerous diseases without evidence of effectiveness. The FDA also banned over-the-counter sale of drug products containing colloidal silver due to the lack of safety or efficacy data. The product now has the status of a dietary supplement in the US; it can be promoted with general "structure-function" claims, but cannot be marketed as preventing or treating any illness.

Following this ruling, the FDA has issued numerous warnings to Internet sites which have continued to promote colloidal silver as an antibiotic or for other medical purposes.

In 2002, the Australian Therapeutic Goods Administration (TGA) ruled that colloidal silver-containing products were no longer exempt from therapeutic goods legislation and had to meet the requirements of other products covered by this law. The TGA found that "there are no current legitimate uses of colloidal silver and that the Surveillance Section of the TGA be requested to investigate the illegal availability of colloidal silver products because of concerns about their significant toxicity. The reasons for the recommendation were that:

There is little evidence to support therapeutic claims made for colloidal silver products; the risk to consumers of silver toxicity outweighs the value of trying an unsubstantiated treatment, and bacterial resistance to silver can occur; and efforts should be made to curb the illegal availability of colloidal silver products, which is a significant public health issue.

See also

• Silver Nano
• Colloidal gold

External links

• "Complementary/Integrative Medicine Therapies: Colloidal Silver". M. D. Anderson Cancer Center.
• "About Herbs: Colloidal Silver". Memorial Sloan-Kettering Cancer Center.
• Wadhera, Akhil (2005). "Systemic argyria associated with ingestion of colloidal silver". Dermatology Online Journal. 11 (1): 12. Retrieved 2006-02-25. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)