Take a look around the grocery store, and you’re likely to see the word “antibacterial” on a variety of cleaning and personal care products, including hand soap, hand sanitizer and dish detergent. As consumers, we like the sound of “antibacterial”. It sounds reassuring.
However, recently published research may give us another reason to read labels and rethink our use of products that contain certain antibacterial agents. Not only are many of them endocrine-disrupting compounds (EDCs), but many have now been associated with increased risk of allergies and food sensitivities.
EDCs include synthetic and naturally occurring chemicals that interfere with normal hormone signaling. Their chemical structures often mimic those of hormones found naturally in our bodies, such as estrogen or estradiol. EDCs have been linked to cancer, reproductive problems, obesity, birth defects, developmental disorders and other medical problems. Many EDCs also have effects on the immune system. For example, exposure to the EDC bisphenol A can increase levels of interleukin-4 and IgE (1), and exposure to triclosan can interfere with cytokine signaling (2–4). Knowing this, the authors of a recent article in the Journal of Allergy and Clinical Immunology (5) set out to discover whether there is an association between EDC exposure and allergies. They also sought to determine if any association was linked to the EDC’s antibacterial properties, as there seems to be a link between the makeup of human intestinal flora and allergies: Antibacterial agents can alter the intestinal flora and may affect the frequency of allergy development. Savage et al. targeted triclosan and methyl, propyl and butyl parabens, which are some of the most common antibacterial agents used in personal care and food products, as well as bisphenol A and benzophenone-3, EDCs that do not have antibacterial properties. They obtained data about urinary concentrations of these chemicals from the 2005–2006 National Health and Nutrition Examination Survey conducted by the US Center for Disease Control and Prevention. They also obtained data about levels of IgE, a class of antibodies associated with allergies. Most allergies and food sensitivities develop between the ages of 6 and 18, so the authors focused on collecting data from children in that age range.
The authors discovered that the odds of developing an allergy or food sensitivity, defined as having an allergen-specific IgE level greater than 0.35kU/L, were higher in children who had higher levels of triclosan, propyl paraben and butyl paraben in their urine and that this association was much stronger in male children. There was no significant association between allergies and levels of bisphenol A and benzophenone-3.
So, how are we exposed to these EDCs? [and many of us in Western society are exposed: For example, CDC researchers detected triclosan in the urine of >70% of people tested (6), while the Environmental Working Group detected it in 89% of people tested.] Certainly, direct exposure through use of products or consumption of food that contain these chemicals is one of the biggest modes of exposure. Many EDCs are lipophilic and are absorbed through the skin. Another is our water supply. Triclosan and bisphenol A survive many wastewater treatment steps and are commonly found in wastewater and surface water samples (7–10). Parabens seemed to removed more efficiently during treatment but still can be detected in treated wastewater and surface water samples (11–14). These chemicals also can accumulate in soil and sediment samples, where they degrade slowly.
The US Federal Drug Administration (FDA) has ruled that these chemicals pose no real public health risks, but they have also concluded that at least one of these EDCs, triclosan, confers few health benefits (15). To avoid adding another pollutant to an already-polluted world, I tend to read labels when I’m shopping and will avoid products with these chemicals when I’m given an alternative EDC-free product. Do you?
- Lee, M.H. et al. (2003) Enhanced interleukin-4 production in CD4+ T cells and elevated immunoglobulin E levels in antigen-primed mice by bisphenol A and nonylphenol, endocrine disruptors: Involvement of nuclear factor-AT and Ca2+. Immunol. 109, 76–86.
- Elwood, C.N. et al. (2007) Triclosan inhibits uropathogenic Escherichia coli-stimulated tumor necrosis factor-alpha secretion in T24 bladder cells in vitro. J. Endourol. 21, 1217–22.
- Modéer, T., Bengtsson, A. and Rölla, G. (1996) Triclosan reduces prostaglandin biosynthesis in human gingival fibroblasts challenged with interleukin-1 in vitro. J. Clin. Periodontol. 23, 927–33.
- Mustafa, M. et al. (2000) Effect of triclosan on interferon-gamma production and major histocompatibility complex class II expression in human gingival fibroblasts. J .Clin. Periodontol. 27, 733–7.
- Savage, J.H. et al. (2012). Urinary levels or triclosan and parabens are associated with aeroallergens and food sensitization. J. Allergy Clin. Immunol. 130, 453–60.
- Calafat, A.M. et al. (2008) Urinary concentrations of triclosan in the U.S. population: 2003–2004. Environ. Health Perspect. 116, 303–7.
- Ricart, M. et al. (2010) Triclosan persistence through wastewater treatment plants and its potential toxic effects on river biofilms. Aquat. Toxicol. 100, 346–53.
- Albero, B. et al. (2012) Occurrence and analysis of parabens in municipal sewage sludge from wastewater treatment plants in Madrid (Spain). J. Hazard. Mater. 239–240, 48–55.
- Kolpin, D.W. et al. (2002) Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999–2000: A national reconnaissance. Environ. Sci. Technol. 36, 1202–11.
- Loraine, G.A. and Pettigrove, M.E. (2006) Seasonal variations in concentrations of pharmaceuticals and personal care products in drinking water and reclaimed wastewater in southern California. Environ. Sci. Technol. 40, 687–95.
- Yamamoto, H. et al. (2007) Preliminary ecological risk assessment of butylparaben and benzylparaben. 1. Removal efficiency in wastewater treatment, acute/chronic toxicity for aquatic organisms, and effects on medaka gene expression. Environ. Sci. 1473–87.
- Jonkers, N. et al. (2009) Mass flows of endocrine disruptors in the Glatt River during varying weather conditions. Environ. Pollut. 157, 714–23.
- Eriksson, E. et al. (2009) Greywater pollution variability and loadings. Ecol. Eng. 35, 661–9.
- Minnesota Department of Health. Drinking water contaminants of emerging concern program. (2010) Triclosan exposure and toxicity summary.
- U S Food and Drug Administration (2010) Triclosan: What consumers should know.
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