molecular mimicry is what makes it an effective antimicrobial.
Another appealing property of triclosan
is that the enzyme to which it binds is present only in bacteria and not in human cells.
Because the enzyme does not exist in our
cells, triclosan cannot bind to it and cause
unintended problems. Due to these unique
properties, hospitals started using triclosan
for surgery in the 1970s.
Triclosan is now used to control outbreaks
of the bacterium methicillin-resistant
Staphylococcus aureus (MRSA), which is often life-threatening for vulnerable hospital patients
and is difficult to treat. Also, in the 1990s,
the U.S. Food and Drug Administration (FDA)
approved the use of triclosan in Colgate Total
toothpaste to fight gingivitis, a form of gum
disease caused by bacteria.
RS GRAPHX, INC., ADAPTED FROM FIGURES AVAILABLE AT: HT TPS://W WW.BOUNDLESS. COM/BIOLOG Y/ TEX TBOOKS/BOUNDLESS-BIOLOGY-TEX TBOOK/BIOLOGICAL-MACROMOLECULES-3/LIPIDS-55/PHOSPHOLIPIDS-300-11433/]
The jury is still out
Triclosan’s molecular mimicry—what
makes it an effective antimicrobial—concerns
many consumers, especially because children
and teens are being exposed to triclosan. In
response to these concerns, companies such
as Johnson & Johnson, L’Oreal, The Body
Shop, and Staples have already removed
triclosan from their products. Crest, one of
Colgate’s major competitors, is advertising its
toothpastes as triclosan-free. One state, Minnesota, has even passed a law to ban triclosan
Where Can You Turn for Good Health Advice? Try looking online for safety facts on triclosan, vaccines, or the ;uoride in your tap water, and you will be confronted with a wide array of Web sites, some reliable and some not so reliable. With so many competing arguments from so many different sources, how do you know which ones to trust? Here is a handy checklist for evaluating Internet claims: What are the writer’s quali;cations? Is the article written by an expert in the ;eld, such as a doctor or scientist? Or is it written by an anonymous source or someone who does not appear to have special expertise in the area? Looking for articles written by sub- ject mattter experts is a good ;rst step. Is the Web site associated with a trusted source? Articles on health associ- ated with organizations such as the U.S. Centers for Disease Control and Prevention, the Mayo Clinic, or The New York Times have typically undergone a quality-control process, ensuring that the information is correct. But if you are reading an article from a newspaper or magazine, check whether it is an editorial! Unlike news articles, which report the facts, editorials often contain authors’ opinions, which may not be helpful. Is the Web site trying to sell you something? If an article ends by trying to sell you a product, such as a supplement that is supposed to detoxify your body of triclo- san, you have good reason to be skeptical! Does the article cite scienti;c studies? Even doctors and scientists sometimes give bad advice on the Internet. One of the best ways to determine whether you should trust an article is whether it backs up its claims with articles published in scienti;c journals. A scienti;c article must undergo a process called peer review, in which other scientists carefully analyze its claims to make sure there are no issues. So, an article based on the scienti;c literature is likely to give you the best advice. Many scienti;c articles are available online for free. —Kristin Harper : : : :
Saturated fatty acid O– O O O CCH2 CH2 CH C R P Unsaturated fatty acid
by 2017—except from Colgate Total, which
was approved by the FDA. The FDA is expected
to issue a ruling on
triclosan’s safety and
efficacy in hand soap
Not everyone is
is bad. Bruce D.
Hammock of the Uni-
versity of California,
Davis, who carried
out a study of the
and risks, says he
is hanging on to his
Colgate Total tooth-
paste and believes
its use in hospitals
is still warranted.
Whatever your posi-
tion is on this con-
remember that you
can always check
the ingredient list on products to determine
whether it is present. Stay tuned for further
Triclosan: What Consumers Should Know. U.S.
Food and Drug Administration, Nov 25,
Nazaryan, A. Is Cancer Lurking in Your Toothpaste?
(And Your Soap? And Your Lipstick?)
Newsweek, Sept 26, 2014: http://www.news-
lipstick-268322.html [accessed Sept 2015].
Figure 3. A cell membrane is made of phospholipid molecules, each consisting
of a hydrophilic head and two hydrophobic tails (shown in more details on the
left). These phospholipid molecules form two layers (top and bottom layers on
the right), with the hydrophobic tails from each layer facing each other and the
hydrophilic heads facing the inside and outside of the cell. The phospholipid
molecules are formed through chemical reactions involving fatty acids, which
consist of a carboxyl group (–COOH) attached to a long carbon chain. When
these chemical reactions are complete, the carboxyl group becomes one of
the two –COO groups seen at the bottom of the hydrophilic head, and the long
carbon chain forms a hydrophobic tail.
Park, A. Can Overuse of Antibacterial Soap Promote
Allergies in Kids? Time, Dec 3, 2010: http://
[accessed Sept 2015].
Kristin Harper is a science writer who lives in
Seattle, Wash. Her latest ChemMatters article,
“So Tired in the Morning: The Science of Sleep,”
appeared in the December 2014/January 2015