How do antibacterial cleaners and soaps do more harm than good?

The company that makes Lysol announced in a television commercial that they are now selling a kind of paper towel soaked in liquid disinfectant, “kills 99.9 percent of germs”, the same percentage that Tide with Bleach claims to wipe out.

There are all sorts of products, hundreds of them, that are advertised as antibacterial, including kitchen cleansers, bathroom cleansers, floor and window cleaners, hand cleaners, antibacterial soaps, hoses, meat slicers, paints, even antiseptic toys.

There are antibacterial plastic food storage containers and knives, antibacterial mattresses, toilet seats, towels, pillows, sheets, slippers, earplugs, plastic water filters, and chopsticks. You can drop all your antibacterial purchases into an antibacterial shopping cart, a company called Rehrig International manufactures a model whose plastic is embedded with an antibacterial substance. Antibacterial claims are now made for more than 700 different products on the market, up from about a dozen in the mid-1990s.

But whatever the advertising for these products may say or imply, there is no scientific evidence anywhere that demonstrates that there are any health benefits whatsoever to using antibacterial cleansers in a healthy household.

On the other hand, there is considerable evidence that the products change the microbial flora of a household, allowing resistant strains of harmful bacteria to flourish, and there are increasing reports of an association between too much hygiene and increased allergies. It may be that excessive hygiene interferes with the normal development of the immune system because it eliminates the stimulation caused by ordinary microflora.

To develop normally, the immune system has to create a balance between the T-helper 1 (TH-1) cells, which provide cellular immunity, and the TH-2 cells, which promote antibody production. People with allergies and eczema have an imbalance between the activities of these two kinds of cells as compared with control groups. In people with allergies, antibody production seems to predominate over cell-mediated responses.

It may be that an “antigenically rich environment” (that’s a fancy way of saying “a dirty house”) may be healthier than one persistently sanitized with antibacterial cleansers.

Glenn Cueman, the president of Microban Products Company, a firm that impregnates many products with triclosan (an antibacterial agent), said in 1998 that “there is no real-world evidence of a link between resistant bacteria and triclosan.” It’s hard to know what Mr. Cueman means by the “real world,” but he was probably wrong when he said this, and he is almost certainly wrong today.

In fact, there are numerous studies that tie the use of triclosan to the development of resistant strains of S. aureus, E. coli, and other germs, specifically because it causes a mutation in a certain gene of these bacteria. This is too bad because triclosan is a useful chemical that will become less and less useful as more resistant strains develop. What there really is “no real-world evidence of ” is any health benefit from embedding triclosan in consumer products.

The development of resistant strains of microbes is a well-known phenomenon in hospitals, and the strains developed vary from one hospital to another. Even hospitals in the same city can have very different patterns of antibiotic resistance, depending on how antibiotics are used.

There is at least some evidence that this can happen in homes where antibacterial products are extensively used, and in any case the theoretical risk is obvious. Some doctors believe that antibacterial soaps, for example, while they may be useful for hand washing, should not be used for bathing, where they will destroy useful bacteria along with the harmful, possibly leading to susceptibility to previously harmless microbes. Nevertheless, there are plenty of antibacterial bath soaps available for anyone who wants to use them.

Antibacterial soaps and cleansers may cause other problems around the house as well, specifically in septic systems. A properly installed and well-operated septic system is a very effective way to recycle waste, but it depends on bacteria for its effectiveness. The bacteria break down waste products, making them harmless or even helpful.

Anaerobic bacteria in the septic system help decompose waste matter, and aerobic bacteria in the soil render pathogens harmless. In other words, these are bacteria you don’t want to kill. Yet antibacterial household products do just that, kill helpful bacteria along with the harmful.

The University of Minnesota Extension Service recommends that “every flush” toilet cleaners not be used with septic tanks, and that only the smallest possible amounts of antibacterial soap, drain cleaners, toilet bowl cleaners, laundry products, tile cleansers, and tub cleaners be flushed into the system, and this includes products labeled “safe for septic systems.”

The use of one product one time may be “safe,” but the cumulative effect of using many of them often can be disastrous. The university recommends further that chlorinated water from swimming pools never be introduced into a septic system, and that unwanted medications never be flushed down the toilet. All this is to preserve the bacteria that do the job of recycling waste products.

The phrase “kills 99.9% of germs” sounds like a classic case of advertising baloney, but it isn’t, at least not completely. It actually refers to a scientific measurement in which 99.9 percent of a standard concentration of germs on an agar plate or other culture medium are killed by the application of a certain concentration of a given antimicrobial substance. That’s why the FTC lets them get away with saying so.

It does not, however, mean that everything you touch with these paper towels will immediately have 0.1 percent of the germs it had before you touched it, although the advertiser will probably not object if you believe this.

About Karen Hill

Karen Hill is a freelance writer, editor, and columnist. Born in New York, her work has appeared in the Examiner, Yahoo News, Buzzfeed, among others.

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