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Are antibacterial soaps better than plain soaps?
University of Michigan researchers reviewed numerous
studies conducted between 1980 and 2006 and concluded that antibacterial
soaps containing triclosan as the main active ingredient are no better at
preventing infections than plain soaps. Further, the team argued that these
antibacterial soaps could actually pose a health risk because they may kill
beneficial bacteria and also reduce the effectiveness of some common
antibiotics, such as amoxicillin. The study was published in the August
2007 issue of the peer-reviewed journal Clinical
Infectious Diseases.
These findings concur with earlier research conducted
by Tufts University’s Alliance for the Prudent Use of Antibiotics.
The Tufts study concluded that overuse of triclosan could cause new strains
of bacteria to develop, thus “changing the kind of bacteria in our
houses to those that may actually be harmful or resistant to
antibiotics,” said Tufts’ Dr. Stuart Levy. The nonprofit group Beyond Pesticides points to
laboratory studies that have found a number of different strains of mutated
bacteria that are resistant to triclosan and to certain antibiotics. The
organization also cites reports of triclosan converting into a carcinogenic
class of chemicals known as dioxins when exposed to water and ultraviolet
radiation. Besides cancer, dioxins have been linked to weakening of the
human immune system, decreased fertility, altered sex hormones, and birth
defects. If antibacterial hand soap is not effective at
reducing infections, consumers may wonder whether alcohol-based hand
sanitizers will do a better job. Combing through different studies on the
topic yields mixed conclusions. According to one study conducted at
Colorado State University, alcohol-based hand sanitizers were as much as
twice as effective as either regular soap or antibacterial soap at reducing
germs on human hands. A Purdue University study, however, contradicts these
findings, concluding that although alcohol-based hand sanitizers may kill
more germs than plain or triclosan-based soaps, they do not prevent more
infections that make people sick. Instead, they may kill the human
body’s own beneficial bacteria by stripping the skin of its outer
layer of oil. The best advice may just come from a study published
in the journal Dairy, Food and Environmental
Sanitation back in 1998, which concluded
that washing hands thoroughly for 20 seconds or more with plain soap and
warm water is by far the most effective way to reduce harmful bacteria and
as such remains our best defense against getting sick.
For more information: Clinical Infectious Diseases,
www.journals.uchicago.edu/CID/; Tufts’ Alliance for the Prudent Use
of Antibiotics, www.tufts.edu/med/apua/; Beyond Pesticides,
www.beyondpesticides.org.
Send questions to Earth Talk, care of E/The Environmental Magazine,
P.O. Box 5098, Westport, CT 06881 or e-mail earthtalk@emagazine.com.
This article appears in Sep 13-19, 2007.
