Introduction

Everyday at work, I don and doff personal protective equipment (gloves, masks, visors, long sleeved gowns, plastic aprons) to prevent the transmission of resistant bacteria from patient to patient. Such is the life of a hospital based infectious diseases physician.

The story does not end there

Another great reason for dressing up in that awful, fussy, restrictive gear is to protect myself from becoming a host to nasty bugs and trafficking them home with me.

The story does not end there either.

We are now learning that there is a major flaw in the whole theory of personal protective equipment. Can you guess what doctors (invariably) bring with them from patient to patient? Apart from our stethoscopes? Yes, our mobile phones.

We are allowed to bring our mobile phones around with us as bleeps and pagers are so out of fashion these days. Studies have shown that mobile phones harbour very nasty bugs indeed. A literature review published in 2015 evaluated the role of communication devices in the spread of infection (1).

The review found that doctors are very poor at cleaning their mobile devices and that these devices are host to pathogens. In fact, only 8% of healthcare workers clean their mobile devices (I am definitely one of that 8%, I promise).

The rate of contamination of mobile devices was very high and ran between 40-80%. Ugh. Remind me never to borrow another doctors phone. The most common pathogens isolated from mobile devices were coagulase negative staphylococci, methicillin sensitive staphylococcus aureus and methicillin resistant staphylococcus aureus.

I attended a conference in the Royal College of Physicians UK last year on ‘superbugs’ and listened to frightening data on the growing problems of antibiotic resistance. One speaker suggested that colloidal silver may hold the key to these superbugs. Naturally, many doctors there wondered about using colloidal silver to reduce our rates of carriage or trafficking of these superbugs.

In fact, colloidal silver phone cases had already been touted as the solution to keep our mobile devices germ free by clever marketers. Believe me when I say that I have a personal vested reason for figuring out if colloidal silver does ‘what it says on the box’.

I checked out one of those awful unsolicited pop-ups on my Facebook feed from an unreasonably popular blog which glorified colloidal silver. Problem was that the blog used as source material other Facebook feeds and Wikipedia. My kids have been told not to use Wikipedia as a reference for their first grade homework. Which self-respecting blogger (or blog owner who outsources to dodgy writers) would use Wikipedia for something this important?

Time to do our own ‘unboxing’ of colloidal silver.

What Actually Is Colloidal Silver?

Silver is an element that is found naturally in the environment as a soft metal or white powder. Sources of silver include drinking water, soil and fresh water in rivers and lakes. It is the 47th element in the periodic table and has an atomic weight of 107.87.

The word silver is believed to derive from the Anglo-saxon word ‘siolfur’. The Latin name for silver is argentum which leads to the common abbreviation for silver of Ag. Silver has the highest conductivity of all metals coupled with the lowest resistance.

Silver is a commodity which is bought, sold and traded. Rich Dad Poor Dad author, Robert Kiyosaki, advocates investing in silver. Silver is widely used in jewellery, electronics, dental fillings, cosmetics photography and medicine. The medicinal use of silver dates back to Avicenna in 980 AD while the more targeted use of silver as an anti-infective dates back to the 1800s.

About 10% of orally ingested silver is absorbed. This percentage goes up in cases where the lining of the mouth or esophagus is damaged. Silver itself can damage the lining of the mouth and intestine. Absorbed silver is excreted in the feces and urine. The body does not need silver for any of is biochemical or physiological processes.

Colloidal silver is a suspension of silver particles in a liquid base.

In August 1999, the FDA banned the use of colloidal silver as the risk-benefit ratio was unfavorable  (2). The FDA do not regulate non-drugs and it is possible to buy colloidal silver in most health food stores and online. There are 425 colloidal silver products for sale on Amazon which cost between $5 and $20 per fluid ounce.

I have listened to a number of webinars on selling physical products on Amazon and it never dawned on me to use that training to bolster my CV. One very astute physician did just that. He scored a publication in a leading journal (JAMA) analysing the Amazon sales ranking for colloidal silver (3).

His publication discusses the fact that there are 24 ingestible products containing colloidal silver listed on the first page of search results on Amazon. He found that 12 of these products had over 10 customer reviews with an average rating of 4.38/5. His bottom line was that it is way too easy to buy colloidal silver online.

Shout out to this researcher for a very smart way to get a publication. So many people work unbelievably hard to try to get a research publication and juggle funding, ethics approval, hiring staff, recruiting patients, analysing statistics while this researcher had a quick look on Amazon and did two (grade 3 level) calculations.

Is There Any Research?

There are 449 publications on colloidal silver and only 3 clinical trials. This compares poorly with mercury which as almost 45,000 publications and over 500 clinical trials. Not to worry about the lack of data, you can always supplement your knowledge base with nuggets of information from randomers on Facebook or some Wikileaks (sorry for the sarcasm but I could not help myself).

Is Colloidal Silver An Antibacterial Agent?

Silver is widely described  as germicidal. The antimicrobial action of silver is believed to relate to the interaction of silver ions with thiol groups which leads to bacterial inactivation. Other proposed mechanisms of action of silver include alteration of the microbial DNA and cell wall degradation.

Ok, enough with the theory. Which bugs does it kill exactly?

In vitro studies have shown that colloidal silver has activity against escherichia coli, staphylococcus aureus, candida albicans, bacillus subtilis, salmonella typhimurium, pseudomonas aeruginosa and klebsiella pneumoniae (4).

Another in vitro study suggests that colloidal silver has larvicical activity against Zika virus, dengue and malaria mosquitos (5).

In vitro means in a test tube. Let’s keep in mind that lots of things can kill bacteria in a test tube but can also kill the person.

One of the major limitations of standard antibiotic therapy is the inability of these antimicrobials to effectively penetrate through biofilms caused by certain bacteria and especially staphylococcus aureus. This is particularly problematic when biofilms are associated with synthetic material such as joint replacements, stents, shunts and grafts.

This often necessitates either removal of the device, use of combination antibiotics (including rifampicin which is usually reserved for TB) and/or life-long suppressive antimicrobial therapy. Preliminary in vitro studies have shown that colloidal silver has activity against biofilms caused by staphylococcus aureus (6).

All very interesting, but what we are not seeing are head-to-head studies e.g. penicillin versus colloidal silver in humans. Without these kinds of studies, we cannot seriously consider silver as an anti-infective agent.

Bottom Line

Silver has not been proven as an antibacterial agent in humans.

Does It Clean Cell Phones?

Perhaps there are studies done by manufacturers of colloidal silver cell phone covers? There are no published studies in the medical literature looking at colloidal silver cell phone covers, wipes or the like.

Bottom Line

There is nothing to support colloidal silver to maintain a germ free phone.

Is It Good For Wound Care Or Skin Health?

Silver is widely used in hospital dressings. In fact, a number of dressings go by the name of ‘Brand Whatever Ag’ as opposed to just ‘Brand Whatever’. The cynic in me has noticed that tagging Ag onto a brand name increases the cost.

Malaysian investigators did a meta-analysis of 14 randomized controlled trials involving 877 patients who had silver dressings or topical treatments for burn wounds (7). The reviewers concluded that ‘silver-containing dressings and topical silver were either no better or worse than control dressings in preventing wound infection and promoting healing of burn wounds’.

Australian investigators did a Cochrane review of silver dressings in diabetic foot infections (8). I have to admit that I was totally shocked at the results. There were no randomized clinical trials on the subject.

The authors concluded that ‘despite the widespread use of dressings and topical agents containing silver for the treatment of diabetic foot ulcers, no randomised trials or controlled clinical trials exist that evaluate their clinical effectiveness’.  I know that lots of our patients are given silver dressings for their diabetic foot ulcers and I had never questioned the source data before (I am as bad as those Wikileaks bloggers).

A total of  26 trials of 2066 patients were included in a Cochrane review to establish the effects of silver-containing wound dressings and topical agents in preventing wound infections and healing wounds (9). Unlike the last Cochrane review, at least there are studies to consider this time. The review found that ‘there is insufficient evidence to establish whether silver-containing dressings or topical agents promote wound healing or prevent wound infection; some poor quality evidence suggests the opposite’.

Bottom Line

There is no evidence to suggest that silver helps skin or wound care. I will never utter the word ‘Ag’ tagged on to the end of the name of a dressing again.

Is It An Anti-inflammatory?

There are no human clinical studies looking at colloidal silver and inflammation.

Bottom Line

Forgive the repetition but there are no studies looking at colloidal silver as an anti-inflammatory.

Does It Help Sinusitis?

As mentioned above, there is emerging evidence to support the role of colloidal silver in treating infectious diseases associated with biofilms.

A study in 8 sheep evaluated the safety and efficacy of topical colloidal silver solution for the treatment of Staphylococcus aureus biofilms (13). The sheep were infected with a biofilm producing from of Staphylococcus aureus and their frontal sinuses were flushed with either silver or saline. Blood silver level, full blood counts, histological samples and biochemical parameters were analyzed.

Sheep treated with colloidal silver showed a statistically significant decrease in biofilm biomass compared to saline control  . Blood silver levels were higher in the treated groups compared to controls but this doe not result in any changes in blood counts or biochemical parameters. Histology and ciliary structure analysis did not show any difference between control and treatment groups.

The authors concluded that silver was safe and effective at reducing the biofilm mass in sheep with sinusitis. This is a good thing and one would hope that this would reduce the symptoms of sinusitis. However silver was not shown to affect the tissues involved in sinusitis. As the sheep cannot tell us how they are feeling, human studies are needed to evaluate the clinical effects of reducing the biolfilm mass in people with sinusitis.

Bottom Line

We have no human data on colloidal silver for sinusitis.

Does It Help The Cold or Flu?

Silver nanoparticles were tested in canine kidney cells infected with influenza virus (14). The silver particles resulted in destruction of viral particles. The second part of the study involved intranasal instillation of silver nanoparticles in mice who had been infected with the influenza virus and showed enhanced survival of cells after influenza infection.

Investigators from Rome studied the efficacy and the safety of a new medical device based on colloidal silver and beta glucan compared with saline solution treatment in a group of 100 children (0-12 years) affected by viral rhinitis (15).

Both the new medical device and saline resulted in a  significant improvement in the Canadian Acute Respiratory Illness and Flu Scale (CARIFS) score.

At the end of treatment, 90% of subjects in the new medical device arm of the study resulted completely recovered, whereas 10% experienced some degree of complications (otitis, tracheitis, bronchitis). In the saline treatment arm, a complete recovering was achieved in 66 % of subjects, the remaining 34 % developed complications. Tolerability profiles were similar in the two groups with no statistical differences in side effects in all age subgroups. This is interesting but millions of miles away from the regular winter coughs, colds and flus that interest us.

Bottom Line

There is no evidence in humans that colloidal silver can help with flus and colds.

Does It Help With Pneumonia?

There are no studies looking at colloidal silver in pneumonia. This surprises me as many blogs claim that colloidal silver is a great option for pneumonia.

A study in mice showed transient moderate active inflammatory changes following direct installation of colloidal silver into the lungs via an endotracheal tube ( a tube that goes from the mouth via the trachea into the lungs) (16). Inflammation can cause or cure pneumonia depending on the type of inflammation.

Silver coated endotracheal tubes have shown to reduce rates of ventilator associated pneumonia (17). People who are admitted to ICU for ventilation have a high risk of developing pneumonia and this is often caused by resistant bacteria. Coating the endotracheal tube with silver has been shown to reduce the risk of developing pneumonia. This was conclusively shown in a study of almost 10,000 ventilated patients in a randomized controlled trial in the USA.

It has to be pointed out that these endotracheal tubes are coated with non-colloidal silver and that this whole process is highly specilaized and is a million miles away from what most other blogs talk about

Bottom Line

There are no studies showing that colloidal silver helps with pneumonia outside of the ICU setting.

Is It Good For Ear Infections Or Pink Eye?

Pink eye refers to redness or swelling of the lining of the eye and is also known as conjunctivitis.

A retrospective study in 8499 women compared silver nitrate, erythromycin, and no eye prophylaxis given at birth for the prevention of conjunctivitis (10). The effect of silver nitrate was modest and was only seen against highly sensitive bacteria.

Kenyan investigators compared silver nitrate drops with tetracycline ointment for the prophylaxis of ophthalmia neonatorum in a controlled trial involving 2732 newborns (11). Prophylaxis with silver nitrate resulted in incidence rates of gonococcal, chlamydial, and nongonococcal, non-chlamydial ophthalmia neonatorum of 0.4, 0.7, and 6.2 percent, while prophylaxis with tetracycline resulted in rates of 0.1, 0.5, and 4.5 percent. The authors concluded that silver and tetracycline are equally efficacious.

A single study showed that silver nitrate drops can help with otitis externa (12). The study compared 1% silver nitrate in 3% hypromellose gel to 0.1% silver nitrate gel in 44 patients with bacterial and fungal external ear infections. The 1% silver nitrate drops was statically significantly better at curing the ear infections.

Bottom Line

There is some preliminary data to suggest that topical  silver nitrate (nitrate and not colloidal silver) can help with conjunctivitis prophylaxis and otitis externa.

Is Colloidal Silver Safe?

The answer to this question is a definite ‘no’ for oral ingestion of colloidal silver. The reference dose for oral silver is 5mcg/day and we get that from regular daily life.

Silver toxicity can cause pleural effusions (fluid building up around the lungs), hemolysis, bone marrow suppression and seizures. It can decrease the absorption of antibiotics and penicillamine. A signature complication of silver overload is known as argyria.

It was Avicenna who first described silver discolouration of the skin. Fuchs coined the term ‘argyria’ in 1840 to describe this odd looking discoloration. Argyria is a complication of chronic silver  overload. There are numerous case reports of argyria in the medical literature.

For example, a 38 year old gentleman was noted to have silver coloured skin , blue nails on a background of having bought colloidal silver for self-management of arthritis for ten months (18). These changes are irreversible (think of the Tinman in the Wizard of Oz).

Conclusion

We, humans, do not need silver for our anatomy, biochemistry or physiology. Therefore, it stands to reason that there is no point in taking supplemental silver. The only possible future role for colloidal silver could be topically or as coating for medical devices- but even these roles are unproven at this time.

The FDA banned the use of colloidal silver and the FDA and FTC have taken manufacturers of colloidal silver to court over false marketing claims and advertising.

I wonder which federal agency oversees ‘false blogging’? Here is the really annoying thing I stumbled upon when researching this blog. As mentioned, a popular (but unscrupulous blog) claims that colloidal silver has umpteen health benefits and uses Wikipedia as a reference. The said same blogger conveniently omits to mention that even Wikipedia categorically advises against the use of colloidal silver.

It would be very easy to write a positive article on almost anything by cherry-picking what to share and how to frame information. That’s unethical, insulting, paternalistic and manipulative. If I cherry-picked what to tell a surgical patient, I could be struck off the medical register for not obtaining ‘informed consent’.

In many ways, health blogs are no different to the clinics. They both aim to educate and inform. Blogs should be honest and balanced. It is definitely ‘false blogging’ to pick and choose what to share with readers.