Effects of triclosan in breast milk on the infant fecal microbiome

Authors: Bever, Candace; RAND, AMY - Carleton University - Canada; NORDING, MALIN - University Of Umea; TAFT, DIANA - University Of California, Davis; KALANETRA, KAREN - University Of California, Davis; MILLS, DAVID - University Of California, Davis; BRECK, MELISSA - University Of California, Davis; SMILOWITZ, JENNIFER - University Of California, Davis; GERMAN, BRUCE - University Of California, Davis; HAMMOCK, BRUCE - University Of California, Davis

Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/26/2018
Publication Date: 3/28/2018
Publication URL: http://handle.nal.usda.gov/10113/5933706
Citation: Bever, C.R., Rand, A., Nording, M., Taft, D., Kalanetra, K.M., Mills, D.A., Breck, M., Smilowitz, J., German, B., Hammock, B.D. 2018. Effects of triclosan in breast milk on the infant fecal microbiome. Chemosphere. 203(2018):467-473. doi:10.1016/j.chemosphere.2018.03.186.
DOI: https://doi.org/10.1016/j.chemosphere.2018.03.186

Interpretive Summary: Many industrial chemicals are finding their way into our bodies. Many personal care products used on a daily basis contain numerous chemicals. One such chemical is triclosan, an antibacterial chemical often used in liquid hand soaps, toothpaste, and many other products. Triclosan is then absorbed by the body and has been detected in human urine, blood, and breast milk. In addition, animal studies have shown that triclosan exerts a wide range of adverse health effects at high (ppm) and low (ppb) concentrations. So, there is a need for methods to improve our ability to measure these harmful chemicals. In this study, we improved methods to extract triclosan from breast milk resulting in no emulsion formation and a higher extraction efficiency. Breast milk donors in this study completed a survey about their use of triclosan-containing personal care products. Of the participants who had detectable amounts of triclosan in their breast milk, nine (75%) of them reported daily use of triclosan-containing personal care products. Also, participants in this study provided stool samples from their infants. These fecal stool samples were compared with the measured triclosan level in their mother’s breast milk. We found that the bacterial diversity in the stool from the infants with detectable amounts of triclosan in their breast milk differed compared to those infants whose mother’s breast milk did not have detectable levels. This finding implies that exogenous chemicals are impacting microbiome diversity.

Technical Abstract: Triclosan is frequently used for its antimicrobial properties and has been detected in human serum, urine, and breast milk. Animal and molecular studies have shown that triclosan exerts a wide range of adverse health effects at both high (ppm) and low (ppb) concentrations. Since triclosan is of growing concern to human and environmental health, there is a need to improve extraction procedures and to study additional effects from triclosan exposure. In this study, we have improved triclosan extraction from breast milk by using salt (MgSO4) to reduce emulsion formation and increase water polarity and water (~80%) to enhance the overall extraction efficiency (~3.5 fold). This extraction method was applied to breast milk samples collected from donors who i) recorded their use of triclosan-containing personal care products and ii) provided matching infant stool samples. Of the participants who had detectable amounts of triclosan in their breast milk, nine (75%) of them reported daily use of triclosan-containing personal care products. Levels of triclosan in breast milk were compared to the donor’s infant’s fecal microbiome. We found that the bacterial diversity in the fecal microbiome of the infants exposed to breast milk with detectable triclosan levels differed compared to their peers exposed to milk containing non-detectable amounts. This finding implies that exogenous chemicals are impacting microbiome diversity.