Is Antibacterial Soap Bad For You? (Part 1)

by David on February 25, 2013

It seems like everything is antibacterial these days, from soaps and lotions to mattress pads and pizza cutters, which really makes you wonder how the world got along before the discovery of Triclosan. Ah, Triclosan, the miracle-working active ingredient in antibacterial soaps, toothpastes, and a galaxy of other consumer products: this unassuming antibacterial compound has infiltrated nearly every aspect of our lives. In my posts for this week and the next I’ll be exploring the profound effects Triclosan has on human health, the environment, and antibiotic resistance, all to answer the (deceptively) simple question: is antibacterial soap bad for you? (The short answer is yes - but not for the reasons you might suspect!)

Bacteria are attacking our pizza? IS NOTHING SACRED

What is Triclosan, and why is it in Pizza cutters?

Triclosan was developed as a broad-spectrum antibiotic (that is, to kill a wide range of bacteria) and has been used in clinical settings since the late ‘60s to help prevent nosocomial (that is, hospital-borne) infections. The first commercial uses of Triclosan appeared during the ‘70s, when it gained popularity as a component of deodorants – no underarm bacteria meant no stinky armpits. In the last few decades, marketers have capitalized on the power of science as an advertising tool and vilified bacteria so successfully that – in addition to deodorants – you can now purchase thousands of products (including pizza cutters) brimming with bacteriocidal Triclosan.

“Out, damn’d spot! out, I say!” – Lady Macbeth, who never used Triclosan

On the importance of hand washing

You’re most likely to notice Triclosan as a component of antibacterial hand soap, and here at MTSG, we take hand washing very seriously. Unfortunately, there is very weak evidence to suggest that the general public is likely to benefit from the addition of Triclosan to hand soap. Although one literature review found antibacterial soaps to be slightly more effective than normal soaps, there is still the matter of a massive epidemiological study that found no significant practical difference between the two. Of course, what you use to wash your hands doesn’t really matter if you dry them off by wiping them off on your pants or using a dirty rag – there’s plenty of evidence that how you choose to dry your hands can enhance or negate the effects of washing them, rendering your choice of soap a moot point.

Heck, just wash your hands with the garden hose and dry ‘em off on a grizzly bear, it’s all the same.

Antibiotic resistance, Problems with

In addition to driving up the cost of hand soap, the inclusion of Triclosan into myriad consumer products appears to be increasing levels of antibiotic resistance in all kinds of bacterial species. It’s a fairly straightforward process: no matter how well you wash your hands, you’re never going to clean off all of the bacteria, and there will always be some that survive the deluge of soap, Triclosan, and water. Often, these bugs survive because they have mutations in their DNA that change some aspect of their biology that prevents the Triclosan from doing what it’s supposed to do. Sometimes, bacteria can exchange these mutated genes (when they confer resistance to antibacterial compounds, we call them “resistance genes”) with one another on little rings of DNA called plasmids. By trading these plasmids like baseball cards, different species of bacteria can pick up all kinds of resistance genes, making infections harder to treat and increasing the number of hospital-borne infections. Of particular concern is that one of the most popular mutations for Triclosan resistance also confers resistance to Isoniazid – an antibiotic used to treat tuberculosis.

They’re useless against TB now, but at least they’re raspberry-flavored!

Human toxicity?

For most of its life, Triclosan has been thought to pose little toxicological risk to humans at the concentrations at which it is normally encountered, but a slew of recent studies have called this safety into question. Researchers have found that Triclosan can potentially mess with sex hormonal activity and seems to exacerbate immune hypersensitivity disorders like allergies and asthma. One study even found that Triclosan could weaken cardiac and skeletal muscles! Granted, the doses involved in these studies are generally fairly high so these findings should be taken with a grain of salt. Even so, when you consider how much of this stuff we’re exposed to on a daily basis, and the fact that Triclosan is easily detected in blood, urine, and breast milk, you may start to wonder about the cumulative effects of all that exposure…

It was then that Anthony realized his mistake. He frolicked not in snow, but pure powdered Triclosan.

Taken together, all of this means that for the average person antibacterial soaps are probably not any more likely to improve their health outcome than washing with boring old regular soap. This is not to say that Triclosan doesn’t have a use, only that its proper use isn’t in consumer products.  When used judiciously, it’s tremendously effective at controlling the spread of microbial disease and nosocomial infections, but when used imprudently, Triclosan may ultimately cause more health problems than it solves.

Tune in next week for part two: Triclosan in the environment!